drm/gpusvm: publish dpagemap early to avoid device mapping leak on error

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "drivers/gpu/drm/drm_gpusvm.c"
                    ],
                    "versions": [
                        {
                            "version": "f70da6f99d4f40c5f481c92e3b65d5e36eaa6dc9",
                            "lessThan": "e8362523fd1b61712f7d996802f9b5dee545c7e6",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "f70da6f99d4f40c5f481c92e3b65d5e36eaa6dc9",
                            "lessThan": "72e4fca5529e45b5beebad79d804de442f632324",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "f70da6f99d4f40c5f481c92e3b65d5e36eaa6dc9",
                            "lessThan": "7f708f51e3955bda0d77a0b67ab9bea6c97fea99",
                            "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/drm_gpusvm.c"
                    ],
                    "versions": [
                        {
                            "version": "6.18",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.18",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.44",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1.6",
                            "lessThanOrEqual": "7.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }