ARM: dts: stm32: Add Ethernet support on stm32mp1

This patch add Ethernet support on stm32mp157 eval board

Signed-off-by: Christophe Roullier <christophe.roullier@st.com>
diff --git a/arch/arm/dts/stm32mp157c-ev1.dts b/arch/arm/dts/stm32mp157c-ev1.dts
index 69980ca..663e52a 100644
--- a/arch/arm/dts/stm32mp157c-ev1.dts
+++ b/arch/arm/dts/stm32mp157c-ev1.dts
@@ -78,7 +78,7 @@
 	pinctrl-0 = <&ethernet0_rgmii_pins_a>;
 	pinctrl-1 = <&ethernet0_rgmii_pins_sleep_a>;
 	pinctrl-names = "default", "sleep";
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-id";
 	max-speed = <1000>;
 	phy-handle = <&phy0>;