drm: move ttm global code to core drm

I wrote this for the prime sharing work, but I also noticed other external
non-upstream drivers from a large company carrying a similiar patch, so I
may as well ship it in master.

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/include/drm/drm.h b/include/drm/drm.h
index e3f46e0..e5f7061 100644
--- a/include/drm/drm.h
+++ b/include/drm/drm.h
@@ -663,6 +663,8 @@
 #define DRM_IOCTL_UNLOCK		DRM_IOW( 0x2b, struct drm_lock)
 #define DRM_IOCTL_FINISH		DRM_IOW( 0x2c, struct drm_lock)
 
+#define DRM_IOCTL_GEM_PRIME_OPEN        DRM_IOWR(0x2e, struct drm_gem_open)
+
 #define DRM_IOCTL_AGP_ACQUIRE		DRM_IO(  0x30)
 #define DRM_IOCTL_AGP_RELEASE		DRM_IO(  0x31)
 #define DRM_IOCTL_AGP_ENABLE		DRM_IOW( 0x32, struct drm_agp_mode)