ARM: dts: sun8i: Add support for qt90h-v4 tablets

The gt90h is a pcb found in generic 9" tablets with an A23 soc, 1G RAM
and 8G nand, rtl8723as usb wifi, 1 micro usb port and 1 micro sd slot.

This commit adds a dts for v4 of the gt90h pcb.

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