cpu/hotplug: fix kabi breakage in enum cpuhp_state

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8JEVI


CVE: NA

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Commit baecdf2dbe73 ("hrtimers: Push pending hrtimers away from outgoing
CPU earlier") add a new step in enum cpuhp_state breaks kabi.

In order to fix the kabi breakage, we had to move the hrtimers:dying
step into smpcfd:dying and create a new function smpcfd_and_hrtimer_dying_cpu().

Signed-off-by: Yu Liao <liaoyu15@huawei.com>