ARM: dts: sun7i: Add dts file for Wits Pro A20 DKT

The Wits Pro A20 DKT is an A20 Development KiT with 1G RAM, 4G NAND,
sdio wifi, 1Gbit ethernet, 1024x768 lcd screen with ft5x_ts touchscreen
and a ton of IO connectors.

Note there seem to be multiple sdcard slots on the board (4 in total), but
other then mmc0 none of these are hooked up by default, there is a ton of
dip-switches which likely allow hooking some of these up, but the
documentation of the board only describes the use of a fraction of them,
so for now we only support mmc0.

Signed-off-by: Jelle de Jong <jelledejong@powercraft.nl>
[hdegoede@redhat.com: Use pwrseq instead of a regulator for the wifi-en pin]
[hdegoede@redhat.com: Add support for OOB irq for the sdio wifi]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>