iwlwifi: use enhance_sensitivity from iwl_fw

Remove another dependency between the nic layer and the iwl_priv
struct.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

diff --cc drivers/net/wireless/iwlwifi/iwl-agn-calib.c
Simple merge

diff --cc drivers/net/wireless/iwlwifi/iwl-dev.h
Simple merge

diff --cc drivers/net/wireless/iwlwifi/iwl-ucode.c
Simple merge