BaseTools/PatchCheck.py: Fix misreport for binary changes in patch

BaseTools/PatchCheck.py: Fix misreport for binary changes in patch

For a patch file that:
1. Contains a binary change
2. Contains any other changes after the binary change

PatchCheck.py will complains with the following error:
* Patch format error: diff found after end of patch
   Line: literal XXXX

This commit resolves this misreport.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>