can: kvaser_usb: get CAN clock frequency from device

The CAN clock frequency is used when calculating the CAN bittiming
parameters. When wrong clock frequency is used, the device may end up
with wrong bittiming parameters, depending on user requested bittiming
parameters.

To avoid this, get the CAN clock frequency from the device. Various
existing Kvaser Leaf products use different CAN clocks.

Fixes: 080f40a6

 ("can: kvaser_usb: Add support for Kvaser CAN/USB devices")
Link: https://lore.kernel.org/all/20211208152122.250852-2-extja@kvaser.com
Cc: stable@vger.kernel.org
Signed-off-by: Jimmy Assarsson <extja@kvaser.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>