CVE-2021-47242 mptcp: fix soft lookup in subflow_error_report()

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "net/mptcp/protocol.c",
      "net/mptcp/subflow.c"
    ],
    "versions": [
      {
        "version": "15cc10453398c22f78f6c2b897119ecce5e5dd89",
        "lessThan": "27ef25c72373222aaa5fe7b5cd890ae9cfb89a8d",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "15cc10453398c22f78f6c2b897119ecce5e5dd89",
        "lessThan": "499ada5073361c631f2a3c4a8aed44d53b6f82ec",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "c8ad65cb5051498b8a58be40499db9e930f0092e",
        "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/mptcp/protocol.c",
      "net/mptcp/subflow.c"
    ],
    "versions": [
      {
        "version": "5.12",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "5.12",
        "status": "unaffected",
        "versionType": "semver"
      },
      {
        "version": "5.12.13",
        "lessThanOrEqual": "5.12.*",
        "status": "unaffected",
        "versionType": "semver"
      },
      {
        "version": "5.13",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]