Replace some custom C11 extension warnings with the generic warning.

llvm-svn: 370066
diff --git a/clang/lib/Parse/ParseExpr.cpp b/clang/lib/Parse/ParseExpr.cpp
index 2eb8ff9..0ced025 100644
--- a/clang/lib/Parse/ParseExpr.cpp
+++ b/clang/lib/Parse/ParseExpr.cpp
@@ -2733,11 +2733,10 @@
 /// \endverbatim
 ExprResult Parser::ParseGenericSelectionExpression() {
   assert(Tok.is(tok::kw__Generic) && "_Generic keyword expected");
-  SourceLocation KeyLoc = ConsumeToken();
-
   if (!getLangOpts().C11)
-    Diag(KeyLoc, diag::ext_c11_generic_selection);
+    Diag(Tok, diag::ext_c11_feature) << Tok.getName();
 
+  SourceLocation KeyLoc = ConsumeToken();
   BalancedDelimiterTracker T(*this, tok::l_paren);
   if (T.expectAndConsume())
     return ExprError();