remove unused iwl4965_init_hw_rates function

The patch removes the unused function to fix a recursive bug caused
by namespace change.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>