iwlagn: reduce severity of disconnected antennas warning

This message is encountered regularly and we need to take a closer look at
the circumstances under which it is printed before presenting errors to
users.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

drivers/net/wireless/iwlwifi/iwl-agn-calib.c

@@ -843,7 +843,7 @@ void iwl_chain_noise_calibration(struct iwl_priv *priv,
 
 	if (active_chains != priv->hw_params.valid_rx_ant &&
 	    active_chains != priv->chain_noise_data.active_chains)
-		IWL_WARN(priv,
+		IWL_DEBUG_CALIB(priv,
 				"Detected that not all antennas are connected! "
 				"Connected: %#x, valid: %#x.\n",
 				active_chains, priv->hw_params.valid_rx_ant);