iwlwifi: mvm: forbid MIMO on devices that don't support it

There are devices that forbid MIMO by the mean of the NVM.
Detect thoses devices and forbid MIMO otherwise the firmware
would crash. STBC is still allowed on these devices.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-eeprom-parse.c b/drivers/net/wireless/iwlwifi/iwl-eeprom-parse.c
index 41ff85d..21302b6 100644
--- a/drivers/net/wireless/iwlwifi/iwl-eeprom-parse.c
+++ b/drivers/net/wireless/iwlwifi/iwl-eeprom-parse.c
@@ -6,6 +6,7 @@
  * GPL LICENSE SUMMARY
  *
  * Copyright(c) 2008 - 2014 Intel Corporation. All rights reserved.
+ * Copyright(c) 2015 Intel Mobile Communications GmbH
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License as
@@ -31,6 +32,7 @@
  * BSD LICENSE
  *
  * Copyright(c) 2005 - 2014 Intel Corporation. All rights reserved.
+ * Copyright(c) 2015 Intel Mobile Communications GmbH
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -748,6 +750,9 @@
 		return;
 	}
 
+	if (data->sku_cap_mimo_disabled)
+		rx_chains = 1;
+
 	ht_info->ht_supported = true;
 	ht_info->cap = IEEE80211_HT_CAP_DSSSCCK40;