drm: hide legacy sg cleanup better from common code

I've decided that some clear markers for what's legacy dri1/non-gem
code is useful. I've opted to use the drm_legacy prefix and then hide
all the checks in that function for better readability in the common
code.

Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index dddd799..743b24d 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -197,11 +197,7 @@
 
 	drm_agp_clear(dev);
 
-	if (drm_core_check_feature(dev, DRIVER_SG) && dev->sg &&
-	    !drm_core_check_feature(dev, DRIVER_MODESET)) {
-		drm_sg_cleanup(dev->sg);
-		dev->sg = NULL;
-	}
+	drm_legacy_sg_cleanup(dev);
 
 	/* Clear vma list (only built for debugging) */
 	list_for_each_entry_safe(vma, vma_temp, &dev->vmalist, head) {