IntelFsp2Pkg: Fix GCC49/XCODE build failure

IntelFsp2Pkg: Fix GCC49/XCODE build failure

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1276

Fixed potentially uninitialized variable build failure
caused by commit: b1cc6f672f3b924cdb190e5b92db3b47f46a8911

Test: Verified on internal platform and boots successfully.

Cc: Jiewen Yao <Jiewen.yao@intel.com>
Cc: Desimone Nathaniel L <nathaniel.l.desimone@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Chasel Chiu <chasel.chiu@intel.com>
Reviewed-by: Jiewen Yao <Jiewen.yao@intel.com>