Backend.cpp: Update DataLayoutPass corresponding to LLVM r217548.

In dragonegg, TheModule always has its DataLayout. No need to give DataLayout(or Module) to DataLayoutPass.

git-svn-id: https://llvm.org/svn/llvm-project/dragonegg/trunk@217562 91177308-0d34-0410-b5e6-96231b3b80d8