can: flexcan: Add quirk to handle separate interrupt lines for mailboxes

Introduce 'FLEXCAN_QUIRK_SECONDARY_MB_IRQ' quirk to handle a FlexCAN
hardware module integration particularity where two ranges of mailboxes
are controlled by separate hardware interrupt lines.
The same 'flexcan_irq' handler is used for both separate mailbox interrupt
lines, with no other changes.

Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://patch.msgid.link/20250113120704.522307-3-ciprianmarian.costea@oss.nxp.com


[mkl: flexcan_open(): change order and free irq_secondary_mb first]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>