pcmcia: at91_cf: fix deferred probe from __init

Move probe out of __init section and don't use platform_driver_probe
which cannot be used with deferred probing.

Since commit e9354576 ("gpiolib: Defer failed gpio requests by default")
this driver might return -EPROBE_DEFER if a gpio_request fails.

Cc: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>