iwl3945: switch to the iwl-core send_card_state routine

Switch iwl3945 to use iwl-core:send_card_state routine.

Signed-off-by: Samuel Ortiz <samuel.ortiz@intel.com>
Signed-off-by: Abhijeet Kolekar <abhijeet.kolekar@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>