Change in coreboot[master]: soc/intel/common/gpio: Add gpio_routes_ioapic_irq function

[Tim Wawrzynczak (Code Review)]

Attention is currently required from: Nico Huber, Furquan Shaikh.
Tim Wawrzynczak has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/49407 )

Change subject: soc/intel/common/gpio: Add gpio_routes_ioapic_irq function
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Patch Set 9:

(1 comment)

File src/soc/intel/common/block/gpio/gpio.c:

https://review.coreboot.org/c/coreboot/+/49407/comment/c9184676_e2b5ad24 
PS7, Line 653: gpio_routes_ioapic_irq
> All excellent points, always one step ahead of me 😉 Let me time this, if it's not too bad, I'd rath […]

Good intuition, I'm measuring about 2.8ms per lookup of IRQ (~300 lookups per IRQ), so like ~350 ns per PCR read (2800 us / 300 GPIOs / 13 IRQs / 2 PCR reads per GPIO). Next patch moves to keeping state, which is already looked up in gpio_configure_itss(), so piggybacking there adds literally 0 boot time, as opposed to ~30ms on Volteer.