UefiCpuPkg: Update BFV searching algorithm in VTF0

UefiCpuPkg: Update BFV searching algorithm in VTF0

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3870
The new algorithm searches FFS3 GUID first and then FFS2 GUID at
every 4KB address in the top 16MB just below 4GB.

Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: Debkumar De <debkumar.de@intel.com>
Cc: Harry Han <harry.han@intel.com>
Cc: Catharine West <catharine.west@intel.com>
Reviewed-by: Min Xu <min.m.xu@intel.com>
Signed-off-by: Ted Kuo <ted.kuo@intel.com>