Rename DEBUG macro to LLVM_DEBUG.
    
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
diff --git a/llvm/lib/Target/Mips/MipsModuleISelDAGToDAG.cpp b/llvm/lib/Target/Mips/MipsModuleISelDAGToDAG.cpp
index ceacaa4..0be5abc 100644
--- a/llvm/lib/Target/Mips/MipsModuleISelDAGToDAG.cpp
+++ b/llvm/lib/Target/Mips/MipsModuleISelDAGToDAG.cpp
@@ -42,7 +42,7 @@
 }
 
 bool MipsModuleDAGToDAGISel::runOnMachineFunction(MachineFunction &MF) {
-  DEBUG(errs() << "In MipsModuleDAGToDAGISel::runMachineFunction\n");
+  LLVM_DEBUG(errs() << "In MipsModuleDAGToDAGISel::runMachineFunction\n");
   auto &TPC = getAnalysis<TargetPassConfig>();
   auto &TM = TPC.getTM<MipsTargetMachine>();
   TM.resetSubtarget(&MF);