CodeGen: Use the new DebugLoc API, NFC

Update lib/CodeGen (and lib/Target) to use the new `DebugLoc` API.

llvm-svn: 233582
diff --git a/llvm/lib/Target/R600/AMDILCFGStructurizer.cpp b/llvm/lib/Target/R600/AMDILCFGStructurizer.cpp
index ee6551b..c9b25a1 100644
--- a/llvm/lib/Target/R600/AMDILCFGStructurizer.cpp
+++ b/llvm/lib/Target/R600/AMDILCFGStructurizer.cpp
@@ -623,7 +623,7 @@
   for (MachineBasicBlock::iterator It = MBB->begin(); It != MBB->end();
       ++It) {
     MachineInstr *instr = &(*It);
-    if (!instr->getDebugLoc().isUnknown())
+    if (instr->getDebugLoc())
       DL = instr->getDebugLoc();
   }
   return DL;