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_scatter.c b/drivers/gpu/drm/drm_scatter.c
index a4a076f..dd8a648 100644
--- a/drivers/gpu/drm/drm_scatter.c
+++ b/drivers/gpu/drm/drm_scatter.c
@@ -46,7 +46,7 @@
 #endif
 }
 
-void drm_sg_cleanup(struct drm_sg_mem * entry)
+static void drm_sg_cleanup(struct drm_sg_mem * entry)
 {
 	struct page *page;
 	int i;
@@ -64,6 +64,14 @@
 	kfree(entry);
 }
 
+void drm_legacy_sg_cleanup(struct drm_device *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;
+	}
+}
 #ifdef _LP64
 # define ScatterHandle(x) (unsigned int)((x >> 32) + (x & ((1L << 32) - 1)))
 #else