iwlwifi: mvm: fix Rx with both chains

commit 5c90422439d6
"iwlwifi: mvm: don't allow diversity if BT Coex / TT forbid it"
broke Rx with 2 chains for diversity.
This had an impact on throughput where we're using only a single
stream (11a/b/g APs, single stream APs, static SMPS).

Fixes: 5c90422439d6 ("iwlwifi: mvm: don't allow diversity if BT Coex / TT forbid it")
Cc: Stable <stable@vger.kernel.org>  [3.16+]
Signed-off-by: Eyal Shapira <eyalx.shapira@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/mvm/utils.c

@@ -665,7 +665,7 @@ bool iwl_mvm_rx_diversity_allowed(struct iwl_mvm *mvm)
 	if (num_of_ant(mvm->fw->valid_rx_ant) == 1)
 		return false;
 
-	if (!mvm->cfg->rx_with_siso_diversity)
+	if (mvm->cfg->rx_with_siso_diversity)
 		return false;
 
 	ieee80211_iterate_active_interfaces_atomic(