BaseTools: Support Structure PCD value assignment in DEC/DSC

https://bugzilla.tianocore.org/show_bug.cgi?id=542
This is pure BaseTools enhancement to support PCD with one structure.
User can specify PCD value based on its structure field.

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

BaseTools/Source/Python/Common/ToolDefClassObject.py

@@ -246,7 +246,6 @@ class ToolDefClassObject(object):
                     Value = Value.replace(Ref, self.MacroDictionary[Ref])
                 else:
                     Value = Value.replace(Ref, self.MacroDictionary[Ref.upper()])
-
         MacroReference = gMacroRefPattern.findall(Value)
         for Ref in MacroReference:
             if Ref not in self.MacroDictionary: