drm/via: vfree() no need checking before calling it

vfree() does it's own NULL checking, no need for explicit check before
calling it.

Signed-off-by: Figo.zhang <figo1802@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
index 409e00a..3273808 100644
--- a/drivers/gpu/drm/via/via_dmablit.c
+++ b/drivers/gpu/drm/via/via_dmablit.c
@@ -195,10 +195,8 @@
 	default:
 		vsg->state = dr_via_sg_init;
 	}
-	if (vsg->bounce_buffer) {
-		vfree(vsg->bounce_buffer);
-		vsg->bounce_buffer = NULL;
-	}
+	vfree(vsg->bounce_buffer);
+	vsg->bounce_buffer = NULL;
 	vsg->free_on_sequence = 0;
 }