Change in coreboot[master]: src/soc/intel/xeon_sp/cpx: Add enable IIO error masks

[Rocky Phagura (Code Review)]

Attention is currently required from: Marc Jones, Jonathan Zhang, Angel Pons, Patrick Rudolph, Tim Chu.
Rocky Phagura has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/50843 )

Change subject: src/soc/intel/xeon_sp/cpx: Add enable IIO error masks
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Patch Set 3:

(1 comment)

File src/soc/intel/xeon_sp/cpx/Kconfig:

https://review.coreboot.org/c/coreboot/+/50843/comment/e2e1a8ba_eee5cd0c 
PS3, Line 16: 	default 4
> This doesn't need to be a config. […]

I thought the PCIE bifurcation could affect this but I think it should be okay. The bifurcation is only for the root ports and doesn't really affect the dynamic number of devices.  Therefore, I've removed the Kconfig option and instead made a #define in pci_devs.h