ARM: sa1100: remove unused board files

The Cerf, H3100, Badge4, Hackkit, LART, NanoEngine, PLEB, Shannon and
Simpad machines were all marked as unused as there are no known users
left. Remove all of these, along with references to them in defconfig
files and drivers.

Four machines remain now: Assabet, Collie (Zaurus SL5500), iPAQ H3600
and Jornada 720, each of which had one person still using them, with
Collie also being supported in Qemu.

Cc: Peter Chubb <peter.chubb@unsw.edu.au>
Cc: Stefan Eletzhofer <stefan.eletzhofer@eletztrick.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Lee Jones <lee@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>