can: kvaser_pciefd: Rename board_irq to pci_irq

can: kvaser_pciefd: Rename board_irq to pci_irq

[ Upstream commit cbf88a6ba7bb6ce0d3131b119298f73bd7b18459 ]

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>
Stable-dep-of: dd885d90c047 ("can: kvaser_pciefd: Use a single write when releasing RX buffers")
Signed-off-by: Sasha Levin <sashal@kernel.org>