drm/amdgpu/vcn4: Prevent OOB reads when parsing dec msg

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "drivers/gpu/drm/amd/amdgpu/vcn_v4_0.c"
                    ],
                    "versions": [
                        {
                            "version": "87cc7f9ebf7ce10f82250002d667ef3e93a79d44",
                            "lessThan": "88411caee8f576d6b5abf6531232fcc0ce756dc5",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "87cc7f9ebf7ce10f82250002d667ef3e93a79d44",
                            "lessThan": "c72a8b4dc6d598e3831ef3abd9c6527dfbf4810e",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "87cc7f9ebf7ce10f82250002d667ef3e93a79d44",
                            "lessThan": "7688143ca62edeecacb3ba0a2cea129dbd262a18",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "87cc7f9ebf7ce10f82250002d667ef3e93a79d44",
                            "lessThan": "63b51e8a9d54317d31cc3856c1e12407070d5fc2",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "87cc7f9ebf7ce10f82250002d667ef3e93a79d44",
                            "lessThan": "3c817a60b09eaab926e475088e750936efcc95ae",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "87cc7f9ebf7ce10f82250002d667ef3e93a79d44",
                            "lessThan": "0a78f2bac1424deb7c9d5e09c6b8e849d8e8b648",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                }

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "drivers/gpu/drm/amd/amdgpu/vcn_v4_0.c"
                    ],
                    "versions": [
                        {
                            "version": "5.13",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.13",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.175",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.140",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.90",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.32",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.0.9",
                            "lessThanOrEqual": "7.0.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }