can: tcan45x: Make wake-up GPIO an optional GPIO

The device has the ability to disable the wake-up pin option. The
wake-up pin can be either force to GND or Vsup and does not have to be
tied to a GPIO. In order for the device to not use the wake-up feature
write the register to disable the WAKE_CONFIG option.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Cc: Sean Nyekjaer <sean@geanix.com>
Reviewed-by: Sean Nyekjaer <sean@geanix.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>