iwl3945: add iwl3945_setup_mac

Patch does following,
1) mac80211's shared data is now initialized in iwl3945_setup_mac.
2) Set the rfkill to right state after initialization

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>