PCMCIA: make lubbock socket driver part of sa1111_cs

Lubbock is just another SA1111 socket driver, so now that Kconfig has
better control of which files get built, we can sanitize the build
for this.

Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>