can: m_can: Reset cached active_interrupts on start

To force writing the enabled interrupts, reset the active_interrupts
cache.

Fixes: 07f25091 ("can: m_can: Implement receive coalescing")
Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Link: https://lore.kernel.org/all/20240805183047.305630-7-msp@baylibre.com


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