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/utils/vim/llvm.vim b/utils/vim/llvm.vim
index 28ab2e3..23802f4 100644
--- a/utils/vim/llvm.vim
+++ b/utils/vim/llvm.vim
@@ -49,6 +49,7 @@
 syn keyword llvmKeyword except deplibs
 syn keyword llvmKeyword volatile fastcc coldcc cc ccc
 syn keyword llvmKeyword x86_stdcallcc x86_fastcallcc
+syn keyword llvmKeyword ptx_kernel ptx_device
 syn keyword llvmKeyword signext zeroext inreg sret nounwind noreturn
 syn keyword llvmKeyword nocapture byval nest readnone readonly noalias
 syn keyword llvmKeyword inlinehint noinline alwaysinline optsize ssp sspreq