iwl3945: use iwl_hw_params in iwl3945_priv

The patch makes changed necessary to use iwl_hw_params to
replace iwl3945_driver_hw_info.

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>