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/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index df8f923..f3a23a3 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -12,7 +12,7 @@
 		drm_platform.o drm_sysfs.o drm_hashtab.o drm_sman.o drm_mm.o \
 		drm_crtc.o drm_modes.o drm_edid.o \
 		drm_info.o drm_debugfs.o drm_encoder_slave.o \
-		drm_trace_points.o
+		drm_trace_points.o drm_global.o
 
 drm-$(CONFIG_COMPAT) += drm_ioc32.o