drm/radeon: Drop drm/ prefix for including drm.h in radeon_drm.h

This allows radeon_drm.h to be reused verbatim in libdrm.
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>

include/uapi/drm/radeon_drm.h

@@ -33,7 +33,7 @@
 #ifndef __RADEON_DRM_H__
 #define __RADEON_DRM_H__
 
-#include <drm/drm.h>
+#include "drm.h"
 
 /* WARNING: If you change any of these defines, make sure to change the
  * defines in the X server file (radeon_sarea.h)