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
diff --git a/llvm/lib/Target/PowerPC/PPCLoopPreIncPrep.cpp b/llvm/lib/Target/PowerPC/PPCLoopPreIncPrep.cpp
index b6e7799..1891b63 100644
--- a/llvm/lib/Target/PowerPC/PPCLoopPreIncPrep.cpp
+++ b/llvm/lib/Target/PowerPC/PPCLoopPreIncPrep.cpp
@@ -87,7 +87,7 @@
     LoopInfo *LI;
     ScalarEvolution *SE;
   };
-}
+} // namespace
 
 char PPCLoopPreIncPrep::ID = 0;
 static const char *name = "Prepare loop for pre-inc. addressing modes";
@@ -113,7 +113,7 @@
   protected:
     ScalarEvolution *SE;
   };
-}
+} // namespace
 
 static bool IsPtrInBounds(Value *BasePtr) {
   Value *StrippedBasePtr = BasePtr;