ARM: remove ebsa110 platform

Russell said that he is no longer using this machine, and it seems that
nobody else has in a long time, so it's time to say goodbye to it.

As this is the last platform using CONFIG_ARCH_USES_GETTIMEOFFSET,
there are some follow-up patches to remove that as well.

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>