init: separate support for GW16109 and GW16107 adapters

The GW16107 provides a GPIO port expander and the GW16109 provides
a touchscreen controller and display. Configure these appropriately.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
init: change CAN bus configuration

Configure for 250kbps send/recv by default and move configuration to the
end of the script so that CAN_ARGS can be changed along the way for specific
baseboards or adapters detected.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>