mt76: mt7915: always check return value from mt7915_mcu_alloc_wtbl_req

As done for mt76_connac_mcu_alloc_wtbl_req, even if this is not a real
bug since mt7915_mcu_alloc_wtbl_req routine can fails just if nskb is NULL,
always check return value from mt7915_mcu_alloc_wtbl_req in order to avoid
possible future mistake.
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7915/mcu.c

@@ -1188,6 +1188,9 @@ mt7915_mcu_sta_ba(struct mt7915_dev *dev,
 
 	wtbl_hdr = mt7915_mcu_alloc_wtbl_req(dev, msta, WTBL_SET, sta_wtbl,
 					     &skb);
+	if (IS_ERR(wtbl_hdr))
+		return PTR_ERR(wtbl_hdr);
+
 	mt7915_mcu_wtbl_ba_tlv(skb, params, enable, tx, sta_wtbl, wtbl_hdr);
 
 	ret = mt76_mcu_skb_send_msg(&dev->mt76, skb,
@@ -1705,6 +1708,9 @@ int mt7915_mcu_sta_update_hdr_trans(struct mt7915_dev *dev,
 		return -ENOMEM;
 
 	wtbl_hdr = mt7915_mcu_alloc_wtbl_req(dev, msta, WTBL_SET, NULL, &skb);
+	if (IS_ERR(wtbl_hdr))
+		return PTR_ERR(wtbl_hdr);
+
 	mt7915_mcu_wtbl_hdr_trans_tlv(skb, vif, sta, NULL, wtbl_hdr);
 
 	return mt76_mcu_skb_send_msg(&dev->mt76, skb, MCU_EXT_CMD(WTBL_UPDATE),
@@ -1729,6 +1735,9 @@ int mt7915_mcu_add_smps(struct mt7915_dev *dev, struct ieee80211_vif *vif,
 
 	wtbl_hdr = mt7915_mcu_alloc_wtbl_req(dev, msta, WTBL_SET, sta_wtbl,
 					     &skb);
+	if (IS_ERR(wtbl_hdr))
+		return PTR_ERR(wtbl_hdr);
+
 	mt7915_mcu_wtbl_smps_tlv(skb, sta, sta_wtbl, wtbl_hdr);
 
 	return mt76_mcu_skb_send_msg(&dev->mt76, skb,
@@ -2254,6 +2263,9 @@ int mt7915_mcu_add_sta(struct mt7915_dev *dev, struct ieee80211_vif *vif,
 
 	wtbl_hdr = mt7915_mcu_alloc_wtbl_req(dev, msta, WTBL_RESET_AND_SET,
 					     sta_wtbl, &skb);
+	if (IS_ERR(wtbl_hdr))
+		return PTR_ERR(wtbl_hdr);
+
 	if (enable) {
 		mt7915_mcu_wtbl_generic_tlv(skb, vif, sta, sta_wtbl, wtbl_hdr);
 		mt7915_mcu_wtbl_hdr_trans_tlv(skb, vif, sta, sta_wtbl, wtbl_hdr);