iwlwifi: mvm: flush all used TX queues before suspending

There is a potential race condition when entering suspend with d0i3 in
PCIe.  If there is a frame queued just before we suspend, it won't
complete and we will never clear the queue stuck timer.  To solve
this, call TX_PATH_FLUSH to flush all queues (except the command
queue) as part of the d0i3 entry process.  Add a new function that
returns all the flushable queues.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
index e9b400c..f002e55 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
@@ -1203,6 +1203,11 @@
 	/* make sure we have no running tx while configuring the seqno */
 	synchronize_net();
 
+	/* Flush the hw queues, in case something got queued during entry */
+	ret = iwl_mvm_flush_tx_path(mvm, iwl_mvm_flushable_queues(mvm), flags);
+	if (ret)
+		return ret;
+
 	/* configure wowlan configuration only if needed */
 	if (mvm->d0i3_ap_sta_id != IWL_MVM_STATION_COUNT) {
 		iwl_mvm_set_wowlan_data(mvm, &wowlan_config_cmd,