sunxi: Add Realtek PHY driver or ARM64 devices

The Orange Pi Zero Plus uses a RTL8211E, add the driver for this PHY.
This is probably used on more boards with a Allwinner SoC.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

target/linux/sunxi/cortexa53/config-default

@@ -92,6 +92,7 @@ CONFIG_PINCTRL_SUN50I_H5=y
 # CONFIG_PINCTRL_SUN9I_A80 is not set
 # CONFIG_PINCTRL_SUN9I_A80_R is not set
 # CONFIG_RANDOMIZE_BASE is not set
+CONFIG_REALTEK_PHY=y
 # CONFIG_SERIAL_AMBA_PL011 is not set
 CONFIG_SOUND_OSS_CORE_PRECLAIM=y
 CONFIG_SPARSEMEM=y