sunxi: gpio: convert bind() to use driver data

Now that the DM core sets driver_data before calling bind(), this driver
can make use of driver_data to determine the set of child devices to
create, rather than manually re-implementing the matching logic in code.

Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>