pcmcia: at91_cf: use module_platform_driver_probe()

Use module_platform_driver_probe() macro which makes the code smaller
and simpler.

Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>