iwlwifi: set hw parameters based on device type

Separate the hw_set_hw_params() function to per device based; different
devices can have different hardware parameters set, when separate the
function based on device type can avoid mistakes, give more flexibilities and
easier to read.

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>