BaseTools: Correct the variable name

the commit bff74750 introduce a undefined variable name 'scope' cause build
failure, it should use 'Scope'.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

BaseTools/Source/Python/GenFds/FdfParser.py

@@ -1135,7 +1135,7 @@ class FdfParser:
     @staticmethod
     def __Verify(Name, Value, Scope):
         # value verification only applies to numeric values.
-        if scope not in TAB_PCD_NUMERIC_TYPES:
+        if Scope not in TAB_PCD_NUMERIC_TYPES:
             return
 
         ValueNumber = 0