drm/gma500: Do not include <drm/drm_global.h>

The gma500 driver has no dependencies on drm_global.h. Remove the include
statement.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180817082138.26628-1-tzimmermann@suse.de

drivers/gpu/drm/gma500/psb_drv.h

@@ -23,7 +23,6 @@
 #include <linux/kref.h>
 
 #include <drm/drmP.h>
-#include <drm/drm_global.h>
 #include <drm/gma_drm.h>
 #include "psb_reg.h"
 #include "psb_intel_drv.h"