Revert "clocksource: Avoid accidental unstable marking of clocksources"

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fd99aeb978451eee9e623be496cd6f9bbbc95e37



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This reverts commit d99e6e1c.

Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>