xfs: directory names are unsigned

Convert the struct xfs_name to use unsigned chars for the name
strings to match both what is stored on disk (__uint8_t) and what
the VFS expects (unsigned char).

Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/xfs_types.h

@@ -151,7 +151,7 @@ typedef enum {
 } xfs_btnum_t;
 
 struct xfs_name {
-	const char	*name;
+	const unsigned char	*name;
 	int			len;
 };