vxlan: check vxlan_vnigroup_init() return value

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "drivers/net/vxlan/vxlan_core.c"
                    ],
                    "versions": [
                        {
                            "version": "f9c4bb0b245cee35ef66f75bf409c9573d934cf9",
                            "lessThan": "79aea5e55156c87dc570e43fcd8bba01b9d6ab3f",
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                        {
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                            "status": "affected",
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                        {
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                            "status": "affected",
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                        },
                        {
                            "version": "f9c4bb0b245cee35ef66f75bf409c9573d934cf9",
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                        {
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                            "status": "affected",
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                    ]
                }

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "drivers/net/vxlan/vxlan_core.c"
                    ],
                    "versions": [
                        {
                            "version": "5.18",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.18",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.129",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.79",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.16",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.13.4",
                            "lessThanOrEqual": "6.13.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.14",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }