Change in coreboot[master]: soc/intel/xeon_sp: Add PCH lockdown

[Angel Pons (Code Review)]

Attention is currently required from: Marc Jones, Furquan Shaikh, Martin Roth, Jonathan Zhang, Johnny Lin, Rocky Phagura, Stefan Reinauer, Patrick Rudolph.
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/49849 )

Change subject: soc/intel/xeon_sp: Add PCH lockdown
......................................................................

Patch Set 3:

(2 comments)

File src/soc/intel/xeon_sp/include/soc/itss.h:

https://review.coreboot.org/c/coreboot/+/49849/comment/5fb39bd3_24756290 
PS3, Line 3: SKL
Hm?

File src/soc/intel/xeon_sp/include/soc/me.h:

https://review.coreboot.org/c/coreboot/+/49849/comment/693b64bd_b6f776aa 
PS3, Line 3: SKYLAKE
hm?