Vlv2TbltDevicePkg: Remove directory assumptions from build scripts

Vlv2TbltDevicePkg: Remove directory assumptions from build scripts

In preparation for moving Vlv2TbltDevicePkg to the
edk2-platforms repository, the batch scripts used to build
this platform are updated to not make any assumptions about
the directory location of Vlv2TbltDevicePkg.

Cc: Zailiang Sun <zailiang.sun@intel.com>
Cc: Yi Qian <yi.qian@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Zailiang Sun <zailiang.sun@intel.com>
Reviewed-by: Yi Qian <yi.qian@intel.com>