gollvm: sync with LLVM change of TargetMachine::addPassesToEmitFile

TargetMachine::addPassesToEmitFile added a DwoOut argument, as of
https://reviews.llvm.org/rL332881

Change-Id: Ief7573088eb6759b63a2136635650dfbb9100731
Reviewed-on: https://go-review.googlesource.com/114088
Reviewed-by: Than McIntosh <thanm@google.com>
diff --git a/driver/CompileGo.cpp b/driver/CompileGo.cpp
index 67aa8d6..2c49b5a 100644
--- a/driver/CompileGo.cpp
+++ b/driver/CompileGo.cpp
@@ -623,7 +623,7 @@
   codeGenPasses.add(new TargetLibraryInfoWrapperPass(*tlii_));
   bool noverify = args_.hasArg(gollvm::options::OPT_noverify);
   TargetMachine::CodeGenFileType ft = TargetMachine::CGFT_AssemblyFile;
-  if (target_->addPassesToEmitFile(codeGenPasses, *OS, ft,
+  if (target_->addPassesToEmitFile(codeGenPasses, *OS, nullptr, ft,
                                    /*DisableVerify=*/ noverify)) {
     errs() << "error: unable to interface with target\n";
     return false;