Factor the common pattern of:

	xfs_dqlock(dqp);
	XFS_DQHOLD(dqp);
	xfs_dqunlock(dqp);

into a new helper, and remove XFS_DQHOLD now that only one other caller
is left.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NBen Myers <bpm@sgi.com>