iwlwifi: Add chain noise scaling factor

6x50 device requires a different scaling factor for Rx gain values sent to
device via PHY_CALIBRATION_CMD (CHAIN_NOISE_GAIN_CMD).  Rather than create
a new iwlXXXX_gain_computation() function, add new chain_noise_scale member
to struct iwl_cfg, and keep using iwl5000_gain_computation().

Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-1000.c b/drivers/net/wireless/iwlwifi/iwl-1000.c
index 9d182067..694ceef 100644
--- a/drivers/net/wireless/iwlwifi/iwl-1000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-1000.c
@@ -247,6 +247,7 @@
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.support_ct_kill_exit = true,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl1000_bg_cfg = {
@@ -274,6 +275,7 @@
 	.chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
 	.support_ct_kill_exit = true,
 	.plcp_delta_threshold = IWL_MAX_PLCP_ERR_THRESHOLD_DEF,
+	.chain_noise_scale = 1000,
 };
 
 MODULE_FIRMWARE(IWL1000_MODULE_FIRMWARE(IWL1000_UCODE_API_MAX));