ARM: dts: uniphier: sync with Linux 4.17-rc6

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/arch/arm/dts/uniphier-ld20-ref.dts b/arch/arm/dts/uniphier-ld20-ref.dts
index 2c1a92f..440c2e6 100644
--- a/arch/arm/dts/uniphier-ld20-ref.dts
+++ b/arch/arm/dts/uniphier-ld20-ref.dts
@@ -67,3 +67,11 @@
 		reg = <0>;
 	};
 };
+
+&pinctrl_ether_rgmii {
+	tx {
+		pins = "RGMII_TXCLK", "RGMII_TXD0", "RGMII_TXD1",
+		       "RGMII_TXD2", "RGMII_TXD3", "RGMII_TXCTL";
+		drive-strength = <9>;
+	};
+};