BaseTools: Remove Makefile/MakefileName fields

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3653

The Makefile and MakefilName fields are never set/used. Remove them.
To check this, the following commands can be used:
- grep -rIn "\.Makefile"
- grep -rIn "\.MakefileName"

Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Reviewed-by: Chris Jones <christopher.jones@arm.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>

BaseTools/Source/Python/AutoGen/ModuleAutoGen.py

@@ -254,7 +254,6 @@ class ModuleAutoGen(AutoGen):
         self.AutoGenDepSet = set()
         self.ReferenceModules = []
         self.ConstPcd                  = {}
-        self.Makefile         = None
         self.FileDependCache  = {}
 
     def __init_platform_info__(self):