The Hummingbird A31 has an AMPAK AP6210 WiFi+Bluetooth module. The
WiFi part is a BCM43362 IC connected to MMC1 in the A31 SoC via SDIO.
The IC also takes a power enable signal via GPIO. This is supported
with the new power sequencing bindings.

The WiFi module supports out-of-band interrupt signaling via GPIO,
but this is not enabled yet.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>