ARM: dts: uniphier: add eMMC pin-mux node

All UniPhier SoCs support an eMMC controller.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

arch/arm/boot/dts/uniphier-pinctrl.dtsi

 /*
  * Device Tree Source for UniPhier SoCs default pinctrl settings
  *
- * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
+ * Copyright (C) 2015-2017 Socionext Inc.
+ *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
  *
  * This file is dual-licensed: you can use it either under the terms
  * of the GPL or the X11 license, at your option. Note that this dual
@@ -43,6 +44,11 @@
  */
 
 &pinctrl {
+	pinctrl_emmc: emmc_grp {
+		groups = "emmc";
+		function = "emmc";
+	};
+
 	pinctrl_i2c0: i2c0_grp {
 		groups = "i2c0";
 		function = "i2c0";