UefiCpuPkg/MpInitLib: Fix a hang in above 4GB case

UefiCpuPkg/MpInitLib: Fix a hang in above 4GB case

This patch fixed the hang in UEFICpuPkg when it is dispatched above 4GB.
In UEFI BIOS case CpuInfoInHob is provided to DXE under 4GB from PEI.
When using UEFI payload and bootloaders, CpuInfoInHob will be allocated
above 4GB since it is not provided from bootloader. so we need update
the code to make sure this hob could be accessed correctly in this case.

Signed-off-by: Guo Dong <guo.dong@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>