drm: mark dma setup/teardown as legacy systems

And hide the checks a bit better. This was already disallowed for
modesetting drivers, so no functinal change here.

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_dma.c b/drivers/gpu/drm/drm_dma.c
index 495b5fd..8a140a9 100644
--- a/drivers/gpu/drm/drm_dma.c
+++ b/drivers/gpu/drm/drm_dma.c
@@ -44,10 +44,18 @@
  *
  * Allocate and initialize a drm_device_dma structure.
  */
-int drm_dma_setup(struct drm_device *dev)
+int drm_legacy_dma_setup(struct drm_device *dev)
 {
 	int i;
 
+	if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA) ||
+	    drm_core_check_feature(dev, DRIVER_MODESET)) {
+		return 0;
+	}
+
+	dev->buf_use = 0;
+	atomic_set(&dev->buf_alloc, 0);
+
 	dev->dma = kzalloc(sizeof(*dev->dma), GFP_KERNEL);
 	if (!dev->dma)
 		return -ENOMEM;
@@ -66,11 +74,16 @@
  * Free all pages associated with DMA buffers, the buffers and pages lists, and
  * finally the drm_device::dma structure itself.
  */
-void drm_dma_takedown(struct drm_device *dev)
+void drm_legacy_dma_takedown(struct drm_device *dev)
 {
 	struct drm_device_dma *dma = dev->dma;
 	int i, j;
 
+	if (!drm_core_check_feature(dev, DRIVER_HAVE_DMA) ||
+	    drm_core_check_feature(dev, DRIVER_MODESET)) {
+		return;
+	}
+
 	if (!dma)
 		return;