Drop useless const in for-range loops.

StringRefs always point to immutable memory so the const doesn't add value
here. Also quiets clang's -Wrange-loop-analysis which warns about the implicit
copying.

llvm-svn: 248496
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index c29059b..0c04213 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -215,7 +215,7 @@
       DAL->AddFlagArg(A, Opts->getOption(options::OPT_Z_Xlinker__no_demangle));
 
       // Add the remaining values as Xlinker arguments.
-      for (const StringRef Val : A->getValues())
+      for (StringRef Val : A->getValues())
         if (Val != "--no-demangle")
           DAL->AddSeparateArg(A, Opts->getOption(options::OPT_Xlinker), Val);
 
@@ -259,7 +259,7 @@
     // Pick up inputs via the -- option.
     if (A->getOption().matches(options::OPT__DASH_DASH)) {
       A->claim();
-      for (const StringRef Val : A->getValues())
+      for (StringRef Val : A->getValues())
         DAL->append(MakeInputArg(*DAL, Opts, Val));
       continue;
     }