drm: msm: Remove stddef.h include from uapi

Having this include here causes sparse to spew an error about
including a file outside of the kerenel repo. There's a
linux/stddef.h file that could be included instead, but things
compile without this include anyway so just remove it.

Change-Id: I320bc9aa23c4e8d75a689efb4c4d0dd2db5e150b
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
index ab38f9e..eb7e0c6 100644
--- a/include/uapi/drm/msm_drm.h
+++ b/include/uapi/drm/msm_drm.h
@@ -19,7 +19,6 @@
 #define __MSM_DRM_H__
 
 #include "drm.h"
-#include <stddef.h>
 #include "sde_drm.h"
 
 #if defined(__cplusplus)