xfs: kill XFS_QMOPT_ASYNC

The option is unused and one of the few remaining users of
xfs_bawrite, so let's get rid of it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Alex Elder <aelder@sgi.com>

fs/xfs/quota/xfs_dquot.c

@@ -1253,8 +1253,6 @@ xfs_qm_dqflush(
 
 	if (flags & XFS_QMOPT_DELWRI) {
 		xfs_bdwrite(mp, bp);
-	} else if (flags & XFS_QMOPT_ASYNC) {
-		error = xfs_bawrite(mp, bp);
 	} else {
 		error = xfs_bwrite(mp, bp);
 	}

fs/xfs/xfs_quota.h

@@ -226,7 +226,6 @@ typedef struct xfs_qoff_logformat {
  * flags for dqflush and dqflush_all.
  */
 #define XFS_QMOPT_SYNC		0x1000000
-#define XFS_QMOPT_ASYNC		0x2000000
 #define XFS_QMOPT_DELWRI	0x4000000
 
 /*