can: gs_usb: gs_can_open(): sort checks for ctrlmode

Sort the checks for dev->can.ctrlmode by values of CAN_CTRLMODE_*, so
that it's clear where to add new checks.

While there, remove the comment that the Atmel UC3C hardware doesn't
support One Shot Mode. The One Shot mode is only available and to be
activated by the user, if the device specifies the feature bit
GS_CAN_FEATURE_ONE_SHOT.

Link: https://lore.kernel.org/all/20221019221016.1659260-3-mkl@pengutronix.de


Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>