ocfs2_quota_wq is not depended upon during memory reclaim and, with
cmwq, there's no reason to use a dedicated workqueue. Drop
ocfs2_quota_wq and use system_wq instead. dqi_sync_work is already
sync canceled on quota disable and no further synchronization is
necessary.
This change makes ocfs2_quota_setup/shutdown() noops. Both functions
removed.
Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <joel.becker@oracle.com>