can: tcan4x5x: add option for selecting nWKRQ voltage

The nWKRQ pin supports an output voltage of either the internal reference
voltage (3.6V) or the reference voltage of
the digital interface 0-6V (VIO).
Add the devicetree option ti,nwkrq-voltage-vio to set it to VIO.

If this property is omitted the reset default, the internal reference
voltage, is used.

Signed-off-by: Sean Nyekjaer <sean@geanix.com>
Reviewed-by: Marc Kleine-Budde <mkl@pengutronix.de>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://patch.msgid.link/20241114-tcan-wkrqv-v5-2-a2d50833ed71@geanix.com


[mkl: remove unused variable in tcan4x5x_get_dt_data()]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>