Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/pps/Kconfig b/drivers/pps/Kconfig
index c6008f2..afbf5e2 100644
--- a/drivers/pps/Kconfig
+++ b/drivers/pps/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # PPS support configuration
 #
@@ -37,8 +38,8 @@
 
 	  It doesn't work on tickless systems at the moment.
 
-source drivers/pps/clients/Kconfig
+source "drivers/pps/clients/Kconfig"
 
-source drivers/pps/generators/Kconfig
+source "drivers/pps/generators/Kconfig"
 
 endif # PPS