ARM: dts: stm32: replace rgmii mode with rgmii-id on stm32mp15 boards

On disco and eval board, Tx and Rx delay are applied (pull-up of 4.7k
put on VDD) so which correspond to RGMII-ID mode with internal RX and TX
delays provided by the PHY, the MAC should not add the RX or TX delays
in this case
Signed-off-by: Christophe Roullier <christophe.roullier@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157a-dk1.dts

@@ -62,7 +62,7 @@ &ethernet0 {
 	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>;
 

arch/arm/boot/dts/stm32mp157c-ev1.dts

@@ -143,7 +143,7 @@ &ethernet0 {
 	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>;