Small C++ PATCH to remove dead code

[Jason Merrill]

This code in store_parm_decls never fired, because we were checking
VOID_TYPE_P on the PARM_DECL itself rather than its type.  And we
already check for void parms in grokparms, so there's no point in
doing it here.

Tested x86_64-pc-linux-gnu, applying to trunk.

commit 7bc6f4c24e2e853ff18bd61f116e02d3b9fe7b6f
Author: Jason Merrill <ja...@redhat.com>
Date:   Mon Jul 11 01:38:35 2016 -0400

        * decl.c (store_parm_decls): Remove check for void parm.

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index c86a131..09bb767 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -14376,13 +14376,7 @@ store_parm_decls (tree current_function_parms)
        {
          next = DECL_CHAIN (parm);
          if (TREE_CODE (parm) == PARM_DECL)
-           {
-             if (DECL_NAME (parm) == NULL_TREE
-                 || !VOID_TYPE_P (parm))
-               pushdecl (parm);
-             else
-               error ("parameter %qD declared void", parm);
-           }
+           pushdecl (parm);
          else
            {
              /* If we find an enum constant or a type tag,