ARM: dts: sun8i: r40: bananapi-m2-ultra: Fix ethernet node

Ethernet PHY on BananaPi M2 Ultra provides RX and TX delays. Fix
ethernet node to reflect that fact.

Fixes: c36fd5a4 ("ARM: dts: sun8i: r40: bananapi-m2-ultra: Enable GMAC ethernet controller")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20201025081949.783443-1-jernej.skrabec@siol.net

arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts

@@ -129,7 +129,7 @@ &gmac {
 	pinctrl-names = "default";
 	pinctrl-0 = <&gmac_rgmii_pins>;
 	phy-handle = <&phy1>;
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-id";
 	phy-supply = <&reg_dc1sw>;
 	status = "okay";
 };