The WiFi side of the AP6212 WiFi/BT combo module is connected to
mmc1. There are also GPIOs for enable and interrupts. An external
clock from the AC100 RTC is also used.

Enable WiFi on this board by enabling mmc1 and adding the power
sequencing clocks and GPIO, as well as the chip's interrupt line.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>