md/dm-raid: don't clear MD_RECOVERY_FROZEN after setting frozen

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9Q98W


CVE: CVE-2024-35808

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MD_RECOVERY_FROZEN should always remain set after array is frozen. But
in raid_message(), this flag is cleared soon after frozen. Fix it. This
flag will be cleared in md_idle_sync_thread(), there is no need to clear
it again for idle.

Fixes: cd32b27a66db ("md/dm-raid: don't call md_reap_sync_thread() directly")
Signed-off-by: Li Nan <linan122@huawei.com>