linux-phytec-ti

dm cache: do not wake_worker() in free_migration()

All methods that queue work call wake_worker() as you'd expect.
E.g. cell_defer, defer_bio, quiesce_migration (which is called by
writeback, promote, demote_then_promote, invalidate, discard, etc).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>