xfs: calculate XFS_TRANS_QM_QUOTAOFF space log reservation at mount time

Convert the calculation of quota off transaction log space reservation
from runtime to mount time.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
CC: Dave Chinner <david@fromorbit.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index fc500c6..4f5e148 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -43,6 +43,7 @@
 	uint	tr_qm_sbchange;	/* change quota flags */
 	uint	tr_qm_setqlim;	/* adjust quota limits */
 	uint	tr_qm_dqalloc;	/* allocate quota on disk */
+	uint	tr_qm_quotaoff;	/* turn quota off */
 } xfs_trans_reservations_t;
 
 #ifndef __KERNEL__