[XS] Change in coreboot[master]: soc/intel/{alderlake, meteorlake}: Properly assign the FSP ASPM UPD

[Tim Crawford (Code Review)]

Attention is currently required from: Felix Singer, Kapil Porwal, Sean Rhodes, Subrata Banik, Tarun Tuli.

Tim Crawford has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/75481?usp=email )

Change subject: soc/intel/{alderlake, meteorlake}: Properly assign the FSP ASPM UPD
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Patch Set 1:

(1 comment)

File src/soc/intel/alderlake/fsp_params.c:

https://review.coreboot.org/c/coreboot/+/75481/comment/eae11359_d6e7fd56 :
PS1, Line 899: 	if (rp_cfg->pcie_rp_aspm)
             : 			s_cfg->PcieRpAspm[i] = get_aspm_control(rp_cfg->pcie_rp_aspm);
             : 		else if (CONFIG(PCIEXP_ASPM)) /* use auto (FSP default) if PCIEXP_ASPM is enabled */
             : 			s_cfg->PcieRpAspm[i] = ASPM_AUTO;
             : 		else
             : 			s_cfg->PcieRpAspm[i] = ASPM_DISABLE;
Those aren't disjoint cases. I want both of them. ASPM should be disabled for a *specific device* BUT be "Auto" for *everything else*.
> we are not relying anywhere on the FSP default value and trying to make sure that coreboot overrides the FSP default as applicable. can you please elaborate

"Auto" has been the default value used by every version of the FSP I've used for porting boards. So I mean setting it to "Auto" is the same thing as setting it to the value already used by the FSP.

It seems like to do what I want, I now have to override `PCIEXP_ASPM` to disable it and specify `pcie_rp_aspm` for *every* device (does that even work if the config is disabled; does FSP do it instead?). Compared to the previous behavior where I only needed to specify the device I want to disable.