iwlwifi: Display sensitivity and chain noise information

Display sensitivity and chain noise data to help understand the current
environment and RF condition.

The data is feeded by statistics notification and Beacon from uCode;
then used by sensitivity calibration and chain noise calibration to
determine how DSP should react to the environment changes

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>