SIO_FIFO_IRQ_NUM macro

\def SIO_FIFO_IRQ_NUM(core) \hideinitializer Returns the irq_num_t for the FIFO IRQ on the given core. \if rp2040_specific On RP2040 each core has a different IRQ number: `SIO_IRQ_PROC0` and `SIO_IRQ_PROC1`. \endif \if rp2350_specific On RP2350 both cores share the same irq number (`SIO_IRQ_PROC`) just with a different SIO interrupt output routed to that IRQ input on each core. \endif Note this macro is intended to resolve at compile time, and does no parameter checking