ARM: dts: sun8i: a83t: Enable both RGMII RX/TX delay on Ethernet PHY

The Ethernet PHY on the Bananapi M3 and Cubietruck Plus have the RX
and TX delays enabled on the PHY, using pull-ups on the RXDLY and
TXDLY pins.

Fix the phy-mode description to correct reflect this so that the
implementation doesn't reconfigure the delays incorrectly. This
happened with commit bbc4d71d6354 ("net: phy: realtek: fix rtl8211e
rx/tx delay config").

Fixes: 039359948a4b ("ARM: dts: sun8i: a83t: Enable Ethernet on two boards")
Signed-off-by: Chen-Yu Tsai <[e-mail]>
Signed-off-by: Maxime Ripard <[e-mail]>
Acked-by: Jernej Skrabec <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/arm/boot/dts/sun8i-a83t-bananapi-m3.dts

···
 	pinctrl-0 = <&emac_rgmii_pins>;
 	phy-supply = <&reg_sw>;
 	phy-handle = <&rgmii_phy>;
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-id";
 	allwinner,rx-delay-ps = <700>;
 	allwinner,tx-delay-ps = <700>;
 	status = "okay";

arch/arm/boot/dts/sun8i-a83t-cubietruck-plus.dts

···
 	pinctrl-0 = <&emac_rgmii_pins>;
 	phy-supply = <&reg_dldo4>;
 	phy-handle = <&rgmii_phy>;
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-id";
 	status = "okay";
 };