UefiCpuPkg/MpInitLib: Avoid call PcdGet* in Ap & Bsp.
MicrocodeDetect function will run by every threads, and it will
use PcdGet to get PcdCpuMicrocodePatchAddress and
PcdCpuMicrocodePatchRegionSize, if change both PCD default to dynamic,
system will in non-deterministic behavior.
By design, UEFI/PI services are single threaded and not re-entrant
so Multi processor code should not use UEFI/PI services. Here, Pcd
protocol/PPI is used to access dynamic PCDs so it would result in
non-deterministic behavior.
This code get PCD value in BSP and save them in CPU_MP_DATA for Ap.