Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/samples/bpf/sock_example.c b/samples/bpf/sock_example.c
index 60ec467..00aae1d 100644
--- a/samples/bpf/sock_example.c
+++ b/samples/bpf/sock_example.c
@@ -99,7 +99,7 @@
 {
 	FILE *f;
 
-	f = popen("ping -c5 localhost", "r");
+	f = popen("ping -4 -c5 localhost", "r");
 	(void)f;
 
 	return test_sock();