[XS] Change in coreboot[main]: drivers/qemu/bochs: Allow building for non-x86 architectures

[Alper Nebi Yasak (Code Review)]

Attention is currently required from: Arthur Heymans, Patrick Rudolph.

Alper Nebi Yasak has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80376?usp=email )

Change subject: drivers/qemu/bochs: Allow building for non-x86 architectures
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Patch Set 2:

(2 comments)

File src/drivers/emulation/qemu/bochs.c:

https://review.coreboot.org/c/coreboot/+/80376/comment/088bfec5_90b9cb81 :
PS1, Line 52: #if CONFIG(CPU_QEMU_X86)
> I saw on your qemu riscv PCI code that you add IO resources to the PCI domain.

To be fair that was mostly verbatim from qemu-aarch64, without me thoroughly understanding it...
> In qemu I see that reading and writing to VIRT_PCIE_PIO should be translated to IO read/writes

This was the key I needed to understand things better and implement those functions, thanks! Now we can use working port I/O instead.

https://review.coreboot.org/c/coreboot/+/80376/comment/3cc9719c_32ae7dcd :
PS1, Line 118: VGA
> When using the legacy BOCHS VGA, which identifies as PCI_CLASS_DISPLAY_VGA, it must use the legacy V […]

I've implemented port I/O functions and removed this config check here. Not exactly sure what you mean with "legacy VGA resources", but I could manage to configure `-device VGA` into text mode. Writing to `0xB8000` doesn't put anything on the display though, so I kept `HAVE_VGA_TEXT_FRAMEBUFFER` still dependent on x86.