arm64: dts: allwinner: Pine H64: Enable both RGMII RX/TX delay

Since commit bbc4d71d63 ("net: phy: realtek: fix rtl8211e rx/tx delay config"),
the network is unusable on PineH64 model A.

This is due to phy-mode incorrectly set to rgmii instead of rgmii-id.

Fixes: 729e1ffcf4 ("arm64: allwinner: h6: add support for the Ethernet on Pine H64")
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20201019063449.33316-1-clabbe@baylibre.com

arch/arm64/boot/dts/allwinner/sun50i-h6-pine-h64.dts

@@ -100,7 +100,7 @@
 &emac {
 	pinctrl-names = "default";
 	pinctrl-0 = <&ext_rgmii_pins>;
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-id";
 	phy-handle = <&ext_rgmii_phy>;
 	phy-supply = <&reg_gmac_3v3>;
 	allwinner,rx-delay-ps = <200>;