Fix handling of curly braces in NVPTX inline asm

Fixes bug 13322

Patch by Dmitry Mikushin

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160050 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 5165193..3df59c3 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -1049,6 +1049,7 @@
       AddrSpaceMap = &NVPTXAddrSpaceMap;
       // Define available target features
       // These must be defined in sorted order!
+      NoAsmVariants = true;
     }
     virtual void getTargetDefines(const LangOptions &Opts,
                                   MacroBuilder &Builder) const {