make arm-use-movt available for all ARM

This updates clang according to a pending patch for llvm to
rename of the -arm-darwin-use-movt to arm-use-movt to make
it available for all of ARM.

note: please apply this close to the llvm change.

Patch by Jeroen Hofstee.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188488 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 2d0998f..9768352 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -832,7 +832,7 @@
 
     // The kext linker doesn't know how to deal with movw/movt.
     CmdArgs.push_back("-backend-option");
-    CmdArgs.push_back("-arm-darwin-use-movt=0");
+    CmdArgs.push_back("-arm-use-movt=0");
   }
 
   // Setting -mno-global-merge disables the codegen global merge pass. Setting