iwlwifi: allow config if device not ready

Allow user to config the device all the time but only allow commiting
these changes to card if the card is up and running.

Signed-off-by: Mohamed Abbas <mohamed.abbas@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>