ARM: SPEAr: DT: Modify DT bindings for STMMAC

This patch modifies the DT bindings for the GMAC IP existings for the
SPEAr family. The DT bindings now additionally pass the phy mode as a
configuration parameter for the ethernet device.

Signed-off-by: Deepak Sikri <deepak.sikri@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
diff --git a/arch/arm/boot/dts/spear600.dtsi b/arch/arm/boot/dts/spear600.dtsi
index a3c36e4..f74feea 100644
--- a/arch/arm/boot/dts/spear600.dtsi
+++ b/arch/arm/boot/dts/spear600.dtsi
@@ -59,6 +59,7 @@
 			interrupt-parent = <&vic1>;
 			interrupts = <24 23>;
 			interrupt-names = "macirq", "eth_wake_irq";
+			phy-mode = "gmii";
 			status = "disabled";
 		};