Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/clk/sprd/mux.h b/drivers/clk/sprd/mux.h
index 548cfa0..892e419 100644
--- a/drivers/clk/sprd/mux.h
+++ b/drivers/clk/sprd/mux.h
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0
+/* SPDX-License-Identifier: GPL-2.0 */
 //
 // Spreadtrum multiplexer clock driver
 //