UefiCpuPkg/ResetVector:Add Option to reserve 4K region at 4GB

UefiCpuPkg/ResetVector:Add Option to reserve 4K region at 4GB

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4140

Some implementations may need to keep the initial Reset code to be
separated out from rest of the code.This request is to add padding at
lower 4K region below 4 GB which will result having only few jmp
instructions and data at that region.

Reviewed-by: Ray Ni <ray.ni@intel.com>
Signed-off-by: Duggapu Chinni B <chinni.b.duggapu@intel.com>