Change in coreboot[master]: *x86: fix x2apic mode boot issue

[Patrick Georgi (Code Review)]

Attention is currently required from: Lance Zhao, Shaunak Saha, Nico Huber, Furquan Shaikh, Wonkyu Kim, Matt DeVillier, Ravishankar Sarawadi, Srinidhi N Kaushik, Subrata Banik.
Patrick Georgi has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/52696 )

Change subject: *x86: fix x2apic mode boot issue
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Patch Set 4:

(1 comment)

File src/include/cpu/x86/lapic.h:

https://review.coreboot.org/c/coreboot/+/52696/comment/b8a50e96_eb1bae76 
PS4, Line 82: 0xb
Not so happy about the magic value here (instead of CPUID_EXTENDED_CPU_TOPOLOGY or something) but the Intel specific CPUID defines are spread out across the entire tree, so there's no obvious place to put it in that is reachable both here and in the SMM stub.

I'd appreciate somebody at Intel to clean that up, so there's a corresponding file to src/include/cpu/amd/cpuid.h but that's out of scope for this change.