drm: fourcc: Use __u32 instead of u32

drm_fourcc.h can be included from user space so use the appropriate types.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

include/drm/drm_fourcc.h

@@ -26,8 +26,8 @@
 
 #include <linux/types.h>
 
-#define fourcc_code(a,b,c,d) ((u32)(a) | ((u32)(b) << 8) | \
-			      ((u32)(c) << 16) | ((u32)(d) << 24))
+#define fourcc_code(a, b, c, d) ((__u32)(a) | ((__u32)(b) << 8) | \
+				 ((__u32)(c) << 16) | ((__u32)(d) << 24))
 
 #define DRM_FORMAT_BIG_ENDIAN (1<<31) /* format is big endian instead of little endian */