iwlwifi: hw_setting cleanup

1. This patch renames hw_setting to hw_params
2. Align names of the structure and variables
3. set_hw_params is called from libs_ops

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>