arm: socfpga: socrates: Add missing PHY skew config

Add missing KSZ9021 PHY skew configuration for the EBV socrates board.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Chin Liang See <clsee@altera.com>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>

arch/arm/dts/socfpga_cyclone5_socrates.dts

@@ -28,6 +28,15 @@
 &gmac1 {
 	status = "okay";
 	phy-mode = "rgmii";
+
+	rxd0-skew-ps = <0>;
+	rxd1-skew-ps = <0>;
+	rxd2-skew-ps = <0>;
+	rxd3-skew-ps = <0>;
+	txen-skew-ps = <0>;
+	txc-skew-ps = <2600>;
+	rxdv-skew-ps = <0>;
+	rxc-skew-ps = <2000>;
 };
 
 &i2c0 {