make arm-use-movt available for all ARM

Before this patch this flag is IOS specific, but is also
useful for bare project like bootloaders / kernels etc,
since movw / movt prevents simple relocation. Therefore
make this flag more commonly available.

note: this patch depends on a similiar rename in clang

Patch by Jeroen Hofstee.

llvm-svn: 188487
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.cpp b/llvm/lib/Target/ARM/ARMSubtarget.cpp
index a94c942..3111f5e 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.cpp
+++ b/llvm/lib/Target/ARM/ARMSubtarget.cpp
@@ -32,7 +32,7 @@
           cl::desc("Reserve R9, making it unavailable as GPR"));
 
 static cl::opt<bool>
-DarwinUseMOVT("arm-darwin-use-movt", cl::init(true), cl::Hidden);
+ArmUseMOVT("arm-use-movt", cl::init(true), cl::Hidden);
 
 static cl::opt<bool>
 UseFusedMulOps("arm-use-mulops",
@@ -169,12 +169,12 @@
   if (isAAPCS_ABI())
     stackAlignment = 8;
 
+  UseMovt = hasV6T2Ops() && ArmUseMOVT;
+
   if (!isTargetIOS()) {
-    UseMovt = hasV6T2Ops();
     IsR9Reserved = ReserveR9;
   } else {
     IsR9Reserved = ReserveR9 | !HasV6Ops;
-    UseMovt = DarwinUseMOVT && hasV6T2Ops();
     SupportsTailCall = !getTargetTriple().isOSVersionLT(5, 0);
   }