[M] Change in coreboot[main]: soc/intel/xeon_sp/smihandler: Lock SMM_FEATURE_CONTROL on all sockets

[Arthur Heymans (Code Review)]

Attention is currently required from: Christian Walter, Johnny Lin, Morgan Jang, Patrick Rudolph, Tim Chu.

Arthur Heymans has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/80247?usp=email )

Change subject: soc/intel/xeon_sp/smihandler: Lock SMM_FEATURE_CONTROL on all sockets
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Patch Set 1: Code-Review+2

(2 comments)

Patchset:

PS1: 
Looks good to me. I don't like that the mainboard code needs boilerplate and will even successfully build if the boilerplate is missing due to weak function. That can be addressed separately though.

File src/mainboard/bytedance/bd_egs/ramstage.c:

https://review.coreboot.org/c/coreboot/+/80247/comment/3622f38c_1afc3397 :
PS1, Line 28: smm_mainboard_pci_resource_store_init
I would be nice to have a soc_ version of this or remove the weak version (Why would anyone select SMM_PCI_RESOURCE_STORE without a valid implementation?) so that the linker is at least unhappy when something is missing.