The sable family (Alphaserver 2000 and 2100) comes in variants for
EV4, EV45, EV5 and EV56. Drop support for the earlier ones that
lack support for the BWX extension but keep the later 'gamma'
variant around since that works with EV56 CPUs.
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>