drm: DRM: fix memset size error

The size passing to memset is wrong.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/char/drm/drm_ioctl.c b/drivers/char/drm/drm_ioctl.c
index d9be146..3cbebf8 100644
--- a/drivers/char/drm/drm_ioctl.c
+++ b/drivers/char/drm/drm_ioctl.c
@@ -272,7 +272,7 @@
 	struct drm_stats *stats = data;
 	int i;
 
-	memset(stats, 0, sizeof(stats));
+	memset(stats, 0, sizeof(*stats));
 
 	mutex_lock(&dev->struct_mutex);