Fixed/added namespace ending comments using clang-tidy. NFC

The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!

llvm-svn: 240137

llvm/lib/CodeGen/DFAPacketizer.cpp

@@ -110,7 +110,7 @@ public:
   // Schedule - Actual scheduling work.
   void schedule() override;
 };
-}
+} // namespace llvm
 
 DefaultVLIWScheduler::DefaultVLIWScheduler(MachineFunction &MF,
                                            MachineLoopInfo &MLI, bool IsPostRA)