drivers: cosmetic: Convert SPDX license tags to Linux Kernel style

Complete in the drivers directory the work started with
commit 83d290c56fab ("SPDX: Convert all of our single
license tags to Linux Kernel style").

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/drivers/clk/altera/Makefile b/drivers/clk/altera/Makefile
index 2542b7f..a3ae8b2 100644
--- a/drivers/clk/altera/Makefile
+++ b/drivers/clk/altera/Makefile
@@ -1,7 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0+
 #
 # Copyright (C) 2018 Marek Vasut <marex@denx.de>
 #
-# SPDX-License-Identifier:      GPL-2.0+
-#
 
 obj-$(CONFIG_TARGET_SOCFPGA_ARRIA10) += clk-arria10.o