[llvm-jitlink] Fix DEBUG_TYPE string.

This updates the DEBUG_TYPE string in llvm-jitlink-macho.cpp to reflect the
change made to llvm-jitlink.cpp in 66128c48400f03f2b423561a63b3e78a355fd349.

Author: lhames

llvm/tools/llvm-jitlink/llvm-jitlink-macho.cpp

@@ -15,7 +15,7 @@
 #include "llvm/Support/Error.h"
 #include "llvm/Support/Path.h"
 
-#define DEBUG_TYPE "llvm-jitlink"
+#define DEBUG_TYPE "llvm_jitlink"
 
 using namespace llvm;
 using namespace llvm::jitlink;