BaseTools: Add Guid name support in GenFfs.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2762

The Fv Section in the FDF files use hard coding Guid values
which is inconvenient to manage. This patch adds Guid name
support in GenFfs to solve this problem.

Signed-off-by: Yuwei Chen <yuwei.chen@intel.com>
Reviewed-by: Bob Feng<bob.c.feng@intel.com>

BaseTools/Source/Python/Common/GlobalData.py

@@ -29,6 +29,7 @@ gProcessingFile = ''
 gBuildingModule = ''
 gSkuids = []
 gDefaultStores = []
+gGuidDict = {}
 
 # definition for a MACRO name.  used to create regular expressions below.
 _MacroNamePattern = "[A-Z][A-Z0-9_]*"