sunxi: Add defconfig for Allwinner A23 EVB

sunxi: Add defconfig for Allwinner A23 EVB

This enables the support for the Allwinner A23 Evaluation Board (EVB),
that already had a device tree (from Linux) but no defconfig.

This board has an AXP223 PMIC, some NAND, Audio out and in plugs, an
accelerometer and light sensor, as well as a USB HSIC hub and a USB
OTG mini-USB connector. It also has a Wifi/BT chip.

Access to the other buses (LCD, MIPI DSI, LVDS, etc) can be done
through dedicated pin headers.

Signed-off-by: Florent Jacquet <florent.jacquet@free-electrons.com>
Cc: Jagan Teki <jagan@openedev.com>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>