Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/testing/selftests/proc/proc-self-syscall.c b/tools/testing/selftests/proc/proc-self-syscall.c
index 5ab5f48..9f6d000 100644
--- a/tools/testing/selftests/proc/proc-self-syscall.c
+++ b/tools/testing/selftests/proc/proc-self-syscall.c
@@ -20,7 +20,6 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <errno.h>
-#include <unistd.h>
 #include <string.h>
 #include <stdio.h>
 
@@ -39,7 +38,7 @@
 	fd = open("/proc/self/syscall", O_RDONLY);
 	if (fd == -1) {
 		if (errno == ENOENT)
-			return 2;
+			return 4;
 		return 1;
 	}