Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/iio/resolver/Makefile b/drivers/iio/resolver/Makefile
index 4e1dcca..fa55813 100644
--- a/drivers/iio/resolver/Makefile
+++ b/drivers/iio/resolver/Makefile
@@ -1,5 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Makefile for Resolver/Synchro drivers
 #
 
+obj-$(CONFIG_AD2S90) += ad2s90.o
 obj-$(CONFIG_AD2S1200) += ad2s1200.o