xfs: convert DM ops to use unsigned char names

dmops uses a signed char for it's namespace event. To be consistent
with the rest of the code, convert them to unsigned char for the
namespace string.

Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index e62fd1c..f4d1441 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -78,7 +78,8 @@
 typedef int	(*xfs_send_namesp_t)(dm_eventtype_t, struct xfs_mount *,
 			struct xfs_inode *, dm_right_t,
 			struct xfs_inode *, dm_right_t,
-			const char *, const char *, mode_t, int, int);
+			const unsigned char *, const unsigned char *,
+			mode_t, int, int);
 typedef int	(*xfs_send_mount_t)(struct xfs_mount *, dm_right_t,
 			char *, char *);
 typedef void	(*xfs_send_unmount_t)(struct xfs_mount *, struct xfs_inode *,