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/NVPTX/NVPTXSubtarget.cpp b/llvm/lib/Target/NVPTX/NVPTXSubtarget.cpp
index 069d6e1..71645dc 100644
--- a/llvm/lib/Target/NVPTX/NVPTXSubtarget.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXSubtarget.cpp
@@ -43,7 +43,7 @@
   return *this;
 }
 
-NVPTXSubtarget::NVPTXSubtarget(const std::string &TT, const std::string &CPU,
+NVPTXSubtarget::NVPTXSubtarget(const Triple &TT, const std::string &CPU,
                                const std::string &FS,
                                const NVPTXTargetMachine &TM)
     : NVPTXGenSubtargetInfo(TT, CPU, FS), PTXVersion(0), SmVersion(20), TM(TM),