Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/samples/v4l/Makefile b/samples/v4l/Makefile
index 65a351d..f86ab12 100644
--- a/samples/v4l/Makefile
+++ b/samples/v4l/Makefile
@@ -1 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_VIDEO_PCI_SKELETON) := v4l2-pci-skeleton.o