ARM: dts: uniphier: add NAND pinmux node

This will be used to set up pin-muxing for the NAND controller.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

arch/arm/dts/uniphier-pinctrl.dtsi

@@ -42,6 +42,11 @@
 		function = "i2c4";
 	};
 
+	pinctrl_nand: nand_grp {
+		groups = "nand";
+		function = "nand";
+	};
+
 	pinctrl_sd: sd_grp {
 		groups = "sd";
 		function = "sd";