Change in coreboot[master]: Rename MMCONF Kconfigs to ECAM_MMCONF

[Tim Wawrzynczak (Code Review)]

Attention is currently required from: Raul Rangel, Mariusz Szafrański, Jonathan Zhang, Paul Menzel, Stefan Reinauer, Kyösti Mälkki, Andrey Petrov, Patrick Rudolph, Nico Huber, Anjaneya "Reddy" Chagam, Johnny Lin, Suresh Bellampalli, Morgan Jang, Michal Motyl, Alexander Couzens, Felix Held, Shelley Chen, Furquan Shaikh, Angel Pons, Lance Zhao, Jason Glenesk, Martin Roth, Damien Zammit, Lee Leahy, Marshall Dawson, Vanessa Eusebio, Huang Jin.
Tim Wawrzynczak has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/57333 )

Change subject: Rename MMCONF Kconfigs to ECAM_MMCONF
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Patch Set 3:

(3 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/57333/comment/ee4bb91a_0b8cc1f3 
PS3, Line 10: pci
nit:
`PCI`

https://review.coreboot.org/c/coreboot/+/57333/comment/c1fdc3a1_876f8b33 
PS3, Line 11: This can be confusing as
            : other platforms, such as ARM, use a different way of mapping the pci
            : config space to memory.
> Out of curiosity, which mechanism does ARM use?

My understanding so far (for QC IIUC) is that there is a single 4K window in MMIO space, and some other device (some kind of address management/translation unit) needs to be informed of the PCI device  you want to access before that can happen so it can expose that PCI device's config space to that single 4K window. Does that sound right Shelley?:

File src/device/Kconfig:

https://review.coreboot.org/c/coreboot/+/57333/comment/ee3ac32e_1be51cef 
PS3, Line 622: 	depends on (ECAM_MMCONF_SUPPORT || PCI_IO_CFG_EXT)
> Does this specifically depend on ECAM, or just MMCONF?

I see what you mean, it really depends on access to PCI config space... hence the `ECAM_MMCONF_SUPPORT || PCI_IO_CFG_EXT`. maybe once this mechanism starts to land we can adapt/see how it fits with the existing PCI(e) infrastructure