Fix pin controller documentation introducing the new compatibles for
the pinctrl drivers specific for aobus / cbus.

This is needed because we have changed the pin controller driver: we
have now a single specialized pinctrl driver / compatible for each bus
the controller is attached to, instead of one single driver dealing with
all the controllers we have on different buses.
Signed-off-by: NCarlo Caione <carlo@endlessm.com>
Acked-by: NRob Herring <robh@kernel.org>