can: m_can: Remove repeated check for is_peripheral

Merge both if-blocks to fix this.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/all/20230315110546.2518305-2-msp@baylibre.com


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