Fix cpplint whitespace/braces issues

Change-Id: Ide80939faf8e8690d8842dde8133902ac725ed1a
diff --git a/compiler/dex/frontend.cc b/compiler/dex/frontend.cc
index 746d475..2d7c973 100644
--- a/compiler/dex/frontend.cc
+++ b/compiler/dex/frontend.cc
@@ -220,7 +220,7 @@
                                        llvm_compilation_unit));
   } else
 #endif
-  {
+  { // NOLINT(whitespace/braces)
     switch (compiler.GetInstructionSet()) {
       case kThumb2:
         cu->cg.reset(ArmCodeGenerator(cu.get(), cu->mir_graph.get(), &cu->arena)); break;