The Ippo-q8h is a tablet circuit board commonly found in cheap Android
tablets with A23 SoCs. There are at least 2 versions of the board, with
different peripherals, such as WiFi chips.

Common features among these tablets include 512 MB DRAM, NAND, MMC, LCD,
capacitive touchscreen, accelerometer, 1 or 2 camera sensors, USB OTG,
microphone and speaker.

v5 of these board designs has a ESP8089 WiFi chip (not supported)
connected to mmc1. This patch adds very basic support.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>