BaseTools: Fix one expression bug to support ~ operate

current use (0x41>=~0x0&0x41|0x0) as Pcd value cause build failure
because the ~ is not correctly recognized.

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/Common/Expression.py

@@ -788,7 +788,7 @@ class ValueExpression(BaseExpression):
         OpToken = ''
         for Ch in Expr:
             if Ch in self.NonLetterOpLst:
-                if '!' == Ch and OpToken:
+                if Ch in ['!', '~'] and OpToken:
                     break
                 self._Idx += 1
                 OpToken += Ch