[OpenCL] Fixed parsing of address spaces for C++.

Added address space tokens to C++ parsing code to be able
to parse declarations that start from an address space keyword.

llvm-svn: 335362
diff --git a/clang/lib/Parse/ParseTentative.cpp b/clang/lib/Parse/ParseTentative.cpp
index dbc8d55..7986054 100644
--- a/clang/lib/Parse/ParseTentative.cpp
+++ b/clang/lib/Parse/ParseTentative.cpp
@@ -1357,6 +1357,11 @@
     // cv-qualifier
   case tok::kw_const:
   case tok::kw_volatile:
+  case tok::kw___private:
+  case tok::kw___local:
+  case tok::kw___global:
+  case tok::kw___constant:
+  case tok::kw___generic:
 
     // GNU
   case tok::kw_restrict: