mt76: mt7615: do not update pm stats in case of error

Do not update pm stats if mt7615_mcu_fw_pmctrl returns an error.

Fixes: abe912ae ("mt76: mt7663: add awake and doze time accounting")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7615/mcu.c

@@ -338,10 +338,11 @@ static int mt7615_mcu_fw_pmctrl(struct mt7615_dev *dev)
 	}
 
 	mt7622_trigger_hif_int(dev, false);
-
+	if (!err) {
 		pm->stats.last_doze_event = jiffies;
 		pm->stats.awake_time += pm->stats.last_doze_event -
 					pm->stats.last_wake_event;
+	}
 out:
 	mutex_unlock(&pm->mutex);