wifi: mt76: mt7996: fix potential memory leakage when reading chip temperature

Without this commit, reading chip temperature will cause memory leakage.

Fixes: 6879b2e9 ("wifi: mt76: mt7996: add thermal sensor device support")
Reported-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Howard Hsu <howard-yh.hsu@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7996/mcu.c

@@ -3750,6 +3750,7 @@ int mt7996_mcu_get_temperature(struct mt7996_phy *phy)
 	} __packed * res;
 	struct sk_buff *skb;
 	int ret;
+	u32 temp;
 
 	ret = mt76_mcu_send_and_get_msg(&phy->dev->mt76, MCU_WM_UNI_CMD(THERMAL),
 					&req, sizeof(req), true, &skb);
@@ -3757,8 +3758,10 @@ int mt7996_mcu_get_temperature(struct mt7996_phy *phy)
 		return ret;
 
 	res = (void *)skb->data;
+	temp = le32_to_cpu(res->temperature);
+	dev_kfree_skb(skb);
 
-	return le32_to_cpu(res->temperature);
+	return temp;
 }
 
 int mt7996_mcu_set_thermal_throttling(struct mt7996_phy *phy, u8 state)