Fix some Clang-tidy modernize warnings, other minor fixes.

Fixed warnings are: modernize-use-override, modernize-use-nullptr and modernize-redundant-void-arg.

Differential revision: http://reviews.llvm.org/D14312

llvm-svn: 252087
diff --git a/llvm/lib/Support/TimeValue.cpp b/llvm/lib/Support/TimeValue.cpp
index 136b93e..94a4c01 100644
--- a/llvm/lib/Support/TimeValue.cpp
+++ b/llvm/lib/Support/TimeValue.cpp
@@ -15,6 +15,7 @@
 #include "llvm/Config/config.h"
 
 namespace llvm {
+
 using namespace sys;
 
 const TimeValue::SecondsType
@@ -22,8 +23,7 @@
 const TimeValue::SecondsType
   TimeValue::Win32ZeroTimeSeconds = -12591158400ULL;
 
-void
-TimeValue::normalize( void ) {
+void TimeValue::normalize() {
   if ( nanos_ >= NANOSECONDS_PER_SECOND ) {
     do {
       seconds_++;
@@ -45,7 +45,7 @@
   }
 }
 
-}
+} // namespace llvm
 
 /// Include the platform-specific portion of TimeValue class
 #ifdef LLVM_ON_UNIX