iwl3945: kill iwl3945_rx_queue_restock

This patch kills iwl3945_rx_queue_restock function on prise of new
hw_params.rx_wrt_ptr_reg which holds per NIC RX write pointer register.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>