ARM: footbridge: remove CATS

Nobody seems to have a CATS machine any more, so remove
it now, leaving only NetWinder and EBSA285.

Cc: Russell King <linux@armlinux.org.uk>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>