SUNRPC: No, I did not intend to create a 256KiB hashtable

Fix the declaration of the gss_auth_hash_table so that it creates
a 16 bucket hashtable, as I had intended.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>