xfs: turn off sign warnings

Because they cause warnings in static inline functions conditionally
compiled into XFS from the VFS (e.g. fsnotify).
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/Makefile

@@ -16,7 +16,7 @@
 # Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #
 
-EXTRA_CFLAGS +=	 -I$(src) -I$(src)/linux-2.6 -Wpointer-sign
+EXTRA_CFLAGS +=	 -I$(src) -I$(src)/linux-2.6
 
 XFS_LINUX := linux-2.6