iwlwifi: separate set_hw_params function for 6000 series

Separate set_hw_params() function for 6000
series from 5000/1000 series because:
    1) 6000 series use different set of sensitivity range table
    2) 6000 series has different uCode image size

Also include the new sensitivity parameters needed by sensitivity
algorithm.

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