Add 'notail' marker for call instructions.

This marker prevents optimization passes from adding 'tail' or
'musttail' markers to a call. Is is used to prevent tail call
optimization from being performed on the call.

rdar://problem/22667622

Differential Revision: http://reviews.llvm.org/D12923

llvm-svn: 252368
diff --git a/llvm/lib/AsmParser/LLToken.h b/llvm/lib/AsmParser/LLToken.h
index ecd6481..6980790 100644
--- a/llvm/lib/AsmParser/LLToken.h
+++ b/llvm/lib/AsmParser/LLToken.h
@@ -54,6 +54,7 @@
     kw_caller,
     kw_tail,
     kw_musttail,
+    kw_notail,
     kw_target,
     kw_triple,
     kw_unwind,