drm: drop drm_buf_t typedef

Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/drm_dma.c b/drivers/char/drm/drm_dma.c
index 2cffb7b..739a6a7 100644
--- a/drivers/char/drm/drm_dma.c
+++ b/drivers/char/drm/drm_dma.c
@@ -129,7 +129,7 @@
  *
  * Resets the fields of \p buf.
  */
-void drm_free_buffer(struct drm_device *dev, drm_buf_t * buf)
+void drm_free_buffer(struct drm_device *dev, struct drm_buf * buf)
 {
 	if (!buf)
 		return;