ARM: dts: aspeed: ast2600-evb: Enable RX delay for MAC0/MAC1

Since mac0/1 and mac2/3 are physically located on different die,
they have different properties by nature, which is mac0/1 has smaller delay step.

The property 'phy-mode' on ast2600 mac0 and mac1 is recommended to set to 'rgmii-rxid'
which enables the RX interface delay from the PHY chip.
Refer page 45 of SDK User Guide v08.00
https://github.com/AspeedTech-BMC/openbmc/releases/download/v08.00/SDK_User_Guide_v08.00.pdf

Fixes: 2ca5646b ("ARM: dts: aspeed: Add AST2600 and EVB")
Signed-off-by: Howard Chiu <howard_chiu@aspeedtech.com>
Link: https://lore.kernel.org/r/SG2PR06MB23152A548AAE81140B57DD69E6E09@SG2PR06MB2315.apcprd06.prod.outlook.comSigned-off-by: Joel Stanley <joel@jms.id.au>

arch/arm/boot/dts/aspeed-ast2600-evb.dts

@@ -103,7 +103,7 @@ ethphy3: ethernet-phy@0 {
 &mac0 {
 	status = "okay";
 
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-rxid";
 	phy-handle = <&ethphy0>;
 
 	pinctrl-names = "default";
@@ -114,7 +114,7 @@ &mac0 {
 &mac1 {
 	status = "okay";
 
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-rxid";
 	phy-handle = <&ethphy1>;
 
 	pinctrl-names = "default";