Vlv2TbltDevicePkg: Allow BaseTools to run from sources

https://bugzilla.tianocore.org/show_bug.cgi?id=258

Update bld_vlv.bat to run BaseTools build command with a call
statement to support running the build command from python
sources.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: David Wei <david.wei@intel.com>
Cc: Mang Guo <mang.guo@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
diff --git a/Vlv2TbltDevicePkg/bld_vlv.bat b/Vlv2TbltDevicePkg/bld_vlv.bat
index e02a605..6c53917 100644
--- a/Vlv2TbltDevicePkg/bld_vlv.bat
+++ b/Vlv2TbltDevicePkg/bld_vlv.bat
@@ -205,7 +205,7 @@
 

 echo.

 echo Invoking EDK2 build...

-build %Build_Flags%

+call build %Build_Flags%

 

 if %ERRORLEVEL% NEQ 0 goto BldFail