xfs: detach inode dquots at the end of inactivation

Once we're done with inactivating an inode, we're finished updating
metadata for that inode.  This means that we can detach the dquots at
the end and not have to wait for reclaim to do it for us.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>