BACKPORT: sched/cpuset: Bring back cpuset_mutex

Turns out percpu_cpuset_rwsem - commit 1243dc51 ("cgroup/cpuset:
Convert cpuset_mutex to percpu_rwsem") - wasn't such a brilliant idea,
as it has been reported to cause slowdowns in workloads that need to
change cpuset configuration frequently and it is also not implementing
priority inheritance (which causes troubles with realtime workloads).

Convert percpu_cpuset_rwsem back to regular cpuset_mutex. Also grab it
only for SCHED_DEADLINE tasks (other policies don't care about stable
cpusets anyway).

Bug: 238390134
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
(cherry picked from commit 111cd11b
https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git

 cgroup/for-6.5)
[Conflicts in all the files. Mostly trivial. cpuset.c had new functions
added on mainline and we rejected lots of hunks related to this new
code. Removed ANDROID specific BUG check that uses cpuset_rwsem which
was a left over from a revert of CPU PAUSE feature that should no longer
exist on 5.15]
Signed-off-by: Qais Yousef <qyousef@google.com>
Change-Id: Ibc77724cdd16a98053b277a79f724bbeb49621de