drm: drop drm_buf_t typedef

Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/i830_drv.h b/drivers/char/drm/i830_drv.h
index bf21703..ddda679 100644
--- a/drivers/char/drm/i830_drv.h
+++ b/drivers/char/drm/i830_drv.h
@@ -95,7 +95,7 @@
 
 	dma_addr_t dma_status_page;
 
-	drm_buf_t *mmap_buffer;
+	struct drm_buf *mmap_buffer;
 
 	u32 front_di1, back_di1, zi1;