iwlwifi: HT antenna/chains overhaul

1. This patch restructures rate scale algorithm to support
   SISO, MIMO2, MIMO3
2. It adds support for detailed valid TX and RX antennas settings
3. It removes few unesfull antenna definitions

Signed-off-by: Guy Cohen <guy.cohen@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -747,7 +747,8 @@ void iwl_chain_noise_calibration(struct iwl_priv *priv,
 			active_chains);
 
 	/* Save for use within RXON, TX, SCAN commands, etc. */
-	priv->valid_antenna = active_chains;
+	/*priv->valid_antenna = active_chains;*/
+	/*FIXME: should be reflected in RX chains in RXON */
 
 	/* Analyze noise for rx balance */
 	average_noise[0] = ((data->chain_noise_a)/CAL_NUM_OF_BEACONS);