[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/MCValue.cpp b/llvm/lib/MC/MCValue.cpp
index 68ecffb..21d9e21 100644
--- a/llvm/lib/MC/MCValue.cpp
+++ b/llvm/lib/MC/MCValue.cpp
@@ -38,6 +38,6 @@
 
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 void MCValue::dump() const {
-  print(dbgs(), 0);
+  print(dbgs(), nullptr);
 }
 #endif