Add ret instruction to PTX backend

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114788 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index 34595e7..23ffd9d 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -544,6 +544,8 @@
   KEYWORD(arm_aapcscc);
   KEYWORD(arm_aapcs_vfpcc);
   KEYWORD(msp430_intrcc);
+  KEYWORD(ptx_kernel);
+  KEYWORD(ptx_device);
 
   KEYWORD(cc);
   KEYWORD(c);