CVE-2026-46257 clocksource/drivers/timer-sp804: Fix an Oops when read_current_timer is called on ARM32 platforms where the SP804 is not registered as the sched_clock.

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "drivers/clocksource/timer-sp804.c"
    ],
    "versions": [
      {
        "version": "640594a04f119338019b0aeed70c7301216595b3",
        "lessThan": "693b0b594b0f278bafa784984129c0c0f988e352",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "640594a04f119338019b0aeed70c7301216595b3",
        "lessThan": "694921a93f3e3621e067afc545cedf6fe3b234a9",
        "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/clocksource/timer-sp804.c"
    ],
    "versions": [
      {
        "version": "6.19",
        "status": "affected"
      },
      {
        "version": "0",
        "lessThan": "6.19",
        "status": "unaffected",
        "versionType": "semver"
      },
      {
        "version": "6.19.4",
        "lessThanOrEqual": "6.19.*",
        "status": "unaffected",
        "versionType": "semver"
      },
      {
        "version": "7.0",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]