Change in coreboot[master]: *x86: Support x2apic mode

[Wonkyu Kim (Code Review)]

Attention is currently required from: Furquan Shaikh, Jamie Ryu, Wonkyu Kim, Subrata Banik, Raj Astekar, Patrick Rudolph.
Hello Lance Zhao, build bot (Jenkins), Furquan Shaikh, Patrick Georgi, Jamie Ryu, Ravishankar Sarawadi, Subrata Banik, Srinidhi N Kaushik, Raj Astekar, Patrick Rudolph,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/51723

to look at the new patch set (#6).

Change subject: *x86: Support x2apic mode
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*x86: Support x2apic mode

Implement x2apic mode as existing code only supports apic mode.
Use info from LAPIC_BASE_MSR(LAPIC_BASE_MSR_X2APIC_MODE) to check
if apic mode or x2apic mode and implment x2apic mode according to
x2apic specfication.

Reference:
https://software.intel.com/content/www/us/en/develop/download/
intel-64-architecture-x2apic-specification.html

BUG=None
BRANCH=None
TEST=boot to OS and check apic mode
cat /proc/cpuinfo | grep "apicid"
ex) can see apicid bigger than 255
apicid          : 256
apicid          : 260

Signed-off-by: Wonkyu Kim 
Change-Id: I0bb729b0521fb9dc38b7981014755daeaf9ca817
---
M src/arch/x86/cpu.c
M src/cpu/x86/lapic/lapic.c
M src/cpu/x86/lapic/lapic_cpu_init.c
M src/cpu/x86/mp_init.c
M src/cpu/x86/smm/smm_stub.S
M src/include/cpu/x86/lapic.h
M src/include/cpu/x86/lapic_def.h
M src/include/cpu/x86/smm.h
8 files changed, 296 insertions(+), 188 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/23/51723/6