drivers/gpu/drm: Remove unnecessary casts of private_data

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index 84c53e4..a823d8f 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -631,7 +631,7 @@
 		return drm_mmap(filp, vma);
 	}
 
-	file_priv = (struct drm_file *)filp->private_data;
+	file_priv = filp->private_data;
 	rdev = file_priv->minor->dev->dev_private;
 	if (rdev == NULL) {
 		return -EINVAL;