pcmcia: pxa2xx: fix logic for lubbock

The lubbock platform uses the sa1111 companion chip with a pxa250
CPU, which means it requires both the PCMCIA_SA1111 and the
PCMCIA_PXA2XX code to be built into the kernel. Unfortunately,
the Makefile and Kconfig don't agree on how this is accomplished,
leading to a situation where you get this link error when building
a lubbock kernel with PCMCIA_SA1111 enabled but PCMCIA_PXA2XX
disabled:

ERROR: "pxa2xx_configure_sockets" [drivers/pcmcia/sa1111_cs.ko] undefined!
ERROR: "pxa2xx_drv_pcmcia_ops" [drivers/pcmcia/sa1111_cs.ko] undefined!
ERROR: "pxa2xx_drv_pcmcia_add_one" [drivers/pcmcia/sa1111_cs.ko] undefined!

This patch changes the Kconfig code to disallow that particular
configuration.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>