BaseTools: GenFds get the Size info for FV image in the FD region

When the FV size is specify in the FD region, Tool generate the FV file
may not use the correct size.

Fixes: https://bugzilla.tianocore.org/show_bug.cgi?id=387
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

BaseTools/Source/Python/GenFds/Fv.py

@@ -1,7 +1,7 @@
 ## @file
 # process FV generation
 #
-#  Copyright (c) 2007 - 2016, Intel Corporation. All rights reserved.<BR>
+#  Copyright (c) 2007 - 2017, Intel Corporation. All rights reserved.<BR>
 #
 #  This program and the accompanying materials
 #  are licensed and made available under the terms and conditions of the BSD License
@@ -50,6 +50,7 @@ class FV (FvClassObject):
         self.CapsuleName = None
         self.FvBaseAddress = None
         self.FvForceRebase = None
+        self.FvRegionInFD = None
         
     ## AddToBuffer()
     #