Implements probe/disconnect for the SDIO device, as well as main
backends for the generic driver to control the SDIO device
(bus_dev_start(), bus_dev_stop() and bus_reset()).

Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>