xfs: make largest supported offset less shouty

XFS_MAXIOFFSET() is just a simple macro that resolves to
mp->m_maxioffset. It doesn't need to exist, and it just makes the
code unnecessarily loud and shouty.

Make it quiet and easy to read.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 9f7ec15..59e22c9 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -273,7 +273,7 @@
 		}
 	}
 
-	n = XFS_MAXIOFFSET(mp) - iocb->ki_pos;
+	n = mp->m_super->s_maxbytes - iocb->ki_pos;
 	if (n <= 0 || size == 0)
 		return 0;