iwlwifi: mvm: use schedule_delayed_work()

There's no need to refer to system_wq directly, use the provided
wrapper schedule_delayed_work().

Made with the following spatch:
    @@
    expression E,F;
    @@
    -queue_delayed_work(system_wq, E, F);
    +schedule_delayed_work(E, F);

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
index 8d1b994..d48c2ec 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/scan.c
@@ -1421,8 +1421,8 @@ int iwl_mvm_reg_scan_start(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
 	mvm->scan_vif = iwl_mvm_vif_from_mac80211(vif);
 	iwl_mvm_ref(mvm, IWL_MVM_REF_SCAN);
 
-	queue_delayed_work(system_wq, &mvm->scan_timeout_dwork,
-			   msecs_to_jiffies(SCAN_TIMEOUT));
+	schedule_delayed_work(&mvm->scan_timeout_dwork,
+			      msecs_to_jiffies(SCAN_TIMEOUT));
 
 	return 0;
 }