[ARM] 5307/1: pxa: fix CM-X2XX PCMCIA build error

Fix build error introduced by commit 27c4cae28148ad97baa2bf8275f7ebc9e2c37c34
[ARM] pxa: allow multi-machine PCMCIA builds

MODPOST 76 modules
ERROR: "cmx270_pcmcia_exit" [drivers/pcmcia/pxa2xx_cm_x2xx.ko] undefined!
ERROR: "cmx255_pcmcia_exit" [drivers/pcmcia/pxa2xx_cm_x2xx.ko] undefined!
ERROR: "cmx270_pcmcia_init" [drivers/pcmcia/pxa2xx_cm_x2xx.ko] undefined!
ERROR: "cmx255_pcmcia_init" [drivers/pcmcia/pxa2xx_cm_x2xx.ko] undefined!
make[2]: *** [__modpost] Error 1
make[1]: *** [modules] Error 2
make: *** [sub-make] Error 2

Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>