serial: UniPhier: support OF configuration

This commit implements the ofdata_to_platdata handler for the UniPhier
serial driver and adds serial device nodes to the device tree sources.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
diff --git a/arch/arm/dts/uniphier-ph1-pro4-ref.dts b/arch/arm/dts/uniphier-ph1-pro4-ref.dts
index 03091a8..b42c9c8 100644
--- a/arch/arm/dts/uniphier-ph1-pro4-ref.dts
+++ b/arch/arm/dts/uniphier-ph1-pro4-ref.dts
@@ -21,5 +21,14 @@
 
 	chosen {
 		bootargs = "console=ttyPS0,115200 earlyprintk";
+		stdout-path = &uart0;
 	};
 };
+
+&uart0 {
+       status = "okay";
+};
+
+&uart1 {
+       status = "okay";
+};