Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/parisc/lib/Makefile b/arch/parisc/lib/Makefile
index f2dac4d..2d7a997 100644
--- a/arch/parisc/lib/Makefile
+++ b/arch/parisc/lib/Makefile
@@ -1,8 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Makefile for parisc-specific library files
 #
 
-lib-y	:= lusercopy.o bitops.o checksum.o io.o memset.o memcpy.o \
-	   ucmpdi2.o delay.o
+lib-y	:= lusercopy.o bitops.o checksum.o io.o memcpy.o \
+	   ucmpdi2.o delay.o string.o
 
 obj-y	:= iomap.o