mon/OSDMonitor: Always tune priority cache manager memory on all mons

mon/OSDMonitor: Always tune priority cache manager memory on all mons

Always call into priority cache manager (pcm) to tune the memory on the
leader and on all the followers (peons) as part of each tick(). This
ensures that the pcm on all the mons continuously tunes the tcmalloc
memory thereby ensuring that the peons don't run out of memory eventually.

Fixes: https://tracker.ceph.com/issues/45266
Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>