ARM: sunxi: dt: add APP4-EVB1 board support

The APP4 EVB1 development boards embeds an A31, together with some NAND, one SD
card slot, and one SDIO + UART WiFi and Bluetooth chip, a few I2C buses, USB,
and a LCD display.

Signed-off-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>