net: remove sb1000 cable modem driver

net: remove sb1000 cable modem driver

This one is hilariously outdated, it provided a faster downlink over
TV cable for users of analog modems in the 1990s, through an ISA card.

The web page for the userspace tools has been broken for 25 years, and
the driver has only ever seen mechanical updates.

Link: http://web.archive.org/web/20000611165545/http://home.adelphia.net:80/~siglercm/sb1000.html
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250312085236.2531870-1-arnd@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>