drm: Use userspace compatible type in fourcc_mod_code macro

__u64 should be used instead of u64.

Feature originally added in:

commit e3eb3250
Author: Rob Clark <robdclark@gmail.com>
Date:   Thu Feb 5 14:41:52 2015 +0000

    drm: add support for tiled/compressed/etc modifier in addfb2
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Daniel Stone <daniels@collabora.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: dri-devel@lists.freedesktop.org
Cc: stable@vger.kernel.org # v4.1+
Fixes: e3eb3250 ("drm: add support for tiled/compressed/etc modifier in addfb2")
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1442999431-28568-1-git-send-email-tvrtko.ursulin@linux.intel.comSigned-off-by: NJani Nikula <jani.nikula@intel.com>

include/uapi/drm/drm_fourcc.h

@@ -158,7 +158,7 @@
 /* add more to the end as needed */
 
 #define fourcc_mod_code(vendor, val) \
-	((((u64)DRM_FORMAT_MOD_VENDOR_## vendor) << 56) | (val & 0x00ffffffffffffffULL))
+	((((__u64)DRM_FORMAT_MOD_VENDOR_## vendor) << 56) | (val & 0x00ffffffffffffffULL))
 
 /*
  * Format Modifier tokens: