IntelFsp2Pkg/FspSecCore: LoadMicrocodeDefault() failed with padding in FV.

IntelFsp2Pkg/FspSecCore: LoadMicrocodeDefault() failed with padding in FV.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3017

Platform microcode FV may have padding between each version of microcode
binary, and current FSP-T/LoadMicrocodeDefault() cannot handle this case
and return not_found unexpectedly.

Cc: Maurice Ma <maurice.ma@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Chasel Chiu <chasel.chiu@intel.com>
Signed-off-by: Cosmo Lai <cosmo.lai@intel.com>
Reviewed-by: Chasel Chiu <chasel.chiu@intel.com>
Reviewed-by: Nate DeSimone <nathaniel.l.desimone@intel.com>