IntelFsp2Pkg/SplitFspBin.py: Support rebasing 1.x binary.

IntelFsp2Pkg/SplitFspBin.py: Support rebasing 1.x binary.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1308

Support rebasing FSP 1.x binary.
FSP 1.x has single component in binary so not supported
by split command and rebase can be done with the same
command for rebasing FSP-T component in FSP 2.x image.

Test: both FSP 2.x (Kabylake) and FSP 1.x (BroadwellDE) binary
      can be rebased successfully.

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