UefiCpuPkg: Fix SMM code hangs when InitPaging

UefiCpuPkg: Fix SMM code hangs when InitPaging

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4246

In function InitPaging, NumberOfPml5Entries is calculated by below code
NumberOfPml5Entries = (UINTN)LShiftU64 (1, SizeOfMemorySpace - 48);
If the SizeOfMemorySpace is larger than 48, NumberOfPml5Entries will be
larger than 1. However, this doesn't make sense if the hardware doesn't
support 5 level page table.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Wu, Jiaxin <jiaxin.wu@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Eric Dong <eric.dong@intel.com>
Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>