net: bridge: mcast: don't truncate the port group walk on teardown

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/bridge/br_multicast.c"
                    ],
                    "versions": [
                        {
                            "version": "b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2",
                            "lessThan": "8243d587a081e790ad96e80d48eef44d9f7ef005",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2",
                            "lessThan": "b45e8c24608c992d1e2cea047eb5bcbfa537f86b",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2",
                            "lessThan": "5a3f7a683aee56e1f15c9d53041f3236767eaae7",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                }

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/bridge/br_multicast.c"
                    ],
                    "versions": [
                        {
                            "version": "5.10",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "5.10",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.59",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.13",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }