ARM: shmobile: lager: tidyup DT node naming

According to ePAPR spec,
this patch tidies up DT node name.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7790-lager-reference.dts

@@ -57,12 +57,12 @@ &pfc {
 	pinctrl-0 = <&scif0_pins &scif1_pins>;
 	pinctrl-names = "default";
 
-	scif0_pins: scif0 {
+	scif0_pins: serial0 {
 		renesas,groups = "scif0_data";
 		renesas,function = "scif0";
 	};
 
-	scif1_pins: scif1 {
+	scif1_pins: serial1 {
 		renesas,groups = "scif1_data";
 		renesas,function = "scif1";
 	};