sched/debug: Reset watchdog on all CPUs while processing sysrq-t

hulk inclusion
category: bugfix
bugzilla: NA
CVE: NA

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Lengthy output of sysrq-t may take a lot of time on slow serial console
with lots of processes and CPUs.

So we need to reset NMI-watchdog to avoid spurious lockup messages, and
we also reset softlockup watchdogs on all other CPUs since another CPU
might be blocked waiting for us to process an IPI or stop_machine.

Signed-off-by: Wei Li <liwei391@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>