Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/clk/imx/clk-imx27.c b/drivers/clk/imx/clk-imx27.c
index 0a0ab95..a375306 100644
--- a/drivers/clk/imx/clk-imx27.c
+++ b/drivers/clk/imx/clk-imx27.c
@@ -3,6 +3,7 @@
 #include <linux/clk-provider.h>
 #include <linux/clkdev.h>
 #include <linux/err.h>
+#include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <dt-bindings/clock/imx27-clock.h>