[C++11] More 'nullptr' conversion or in some cases just using a boolean check instead of comparing to nullptr.

llvm-svn: 206129
diff --git a/llvm/lib/MC/MCInst.cpp b/llvm/lib/MC/MCInst.cpp
index 124cc14..d7b80f5 100644
--- a/llvm/lib/MC/MCInst.cpp
+++ b/llvm/lib/MC/MCInst.cpp
@@ -34,7 +34,7 @@
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 void MCOperand::dump() const {
-  print(dbgs(), 0);
+  print(dbgs(), nullptr);
   dbgs() << "\n";
 }
 #endif
@@ -66,7 +66,7 @@
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 void MCInst::dump() const {
-  print(dbgs(), 0);
+  print(dbgs(), nullptr);
   dbgs() << "\n";
 }
 #endif