iwlwifi: remove radio disable parameter.

Patch removes the "manual radio disable" parameter
as there is no usage scenario of disabling radio using this module parameter.
User can use iwconfig's txpower to enable and disable radio.

This module parameter also does not work as expected. During module load
the status of radio is set, the radio is not actually disabled. Even so,
the moment mac80211 requests the interface to be up the radio will be
enabled again.

Signed-off-by: Abhijeet Kolekar <abhijeet.kolekar@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>