Add the private keyword to the VIM syntax highlighting.

llvm-svn: 76134
diff --git a/llvm/utils/vim/llvm.vim b/llvm/utils/vim/llvm.vim
index b4104f9..d70e651 100644
--- a/llvm/utils/vim/llvm.vim
+++ b/llvm/utils/vim/llvm.vim
@@ -40,7 +40,7 @@
 
 " Keywords.
 syn keyword llvmKeyword define declare global constant
-syn keyword llvmKeyword internal external
+syn keyword llvmKeyword internal external private
 syn keyword llvmKeyword linkonce linkonce_odr weak weak_odr appending
 syn keyword llvmKeyword common extern_weak
 syn keyword llvmKeyword thread_local dllimport dllexport