Replace string GNU Triples with llvm::Triple in MCSubtargetInfo and create*MCSubtargetInfo(). NFC.

Summary:
This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: rafael

Reviewed By: rafael

Subscribers: rafael, ted, jfb, llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10311

llvm-svn: 239467
diff --git a/llvm/lib/Target/MSP430/MSP430TargetMachine.cpp b/llvm/lib/Target/MSP430/MSP430TargetMachine.cpp
index d6cc4ae..e668225 100644
--- a/llvm/lib/Target/MSP430/MSP430TargetMachine.cpp
+++ b/llvm/lib/Target/MSP430/MSP430TargetMachine.cpp
@@ -34,7 +34,7 @@
                         Options, RM, CM, OL),
       TLOF(make_unique<TargetLoweringObjectFileELF>()),
       // FIXME: Check DataLayout string.
-      Subtarget(TT, CPU, FS, *this) {
+      Subtarget(Triple(TT), CPU, FS, *this) {
   initAsmInfo();
 }