can: kvaser_pciefd: Rename board_irq to pci_irq

Rename the variable name board_irq in the ISR to pci_irq to
be more specific and to match the macro by which it is read.

Signed-off-by: Martin Jocic <martin.jocic@kvaser.com>
Link: https://lore.kernel.org/all/20240614151524.2718287-7-martin.jocic@kvaser.com


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