The CubieTruck has an AMPAK AP6210 WiFi+Bluetooth module. The WiFi
part is a BCM43362 IC connected to MMC3 in the A20 SoC via SDIO.
The IC also takes a power enable signal via GPIO.

The WiFi module supports out-of-band interrupt signaling via GPIO,
but this is not supported in this patch.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>