fix: doc: in kernel/drivers interrupts function had mismatching types

The typedef defines an interrupt config routine with `const struct device
*dev`, while the example function had (void) as argument. This could be
considered confusing / would throw compiler warnings even though the
parameter isn't strictly necessary.

Code examples for initializing an IRQ in a device example follow the
updated pattern (e.g. see `drivers/serial/uart_npcx.c`).

Signed-off-by: Sophie Tyalie <dev@flowerpot.me>