mt76: mt7915: disable UL MU-MIMO for mt7915

After initially establishing a connection, it can produce multi-second latency
spikes and tx hangs when pushing traffic.
It should work better for MT7916 and MT7986, so leave it enabled there
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -753,8 +753,9 @@ mt7915_set_stream_he_txbf_caps(struct mt7915_dev *dev,
 
 	elem->phy_cap_info[7] &= ~IEEE80211_HE_PHY_CAP7_MAX_NC_MASK;
 
-	c = IEEE80211_HE_PHY_CAP2_NDP_4x_LTF_AND_3_2US |
-	    IEEE80211_HE_PHY_CAP2_UL_MU_FULL_MU_MIMO |
+	c = IEEE80211_HE_PHY_CAP2_NDP_4x_LTF_AND_3_2US;
+	if (!is_mt7915(&dev->mt76))
+		c |= IEEE80211_HE_PHY_CAP2_UL_MU_FULL_MU_MIMO |
 		     IEEE80211_HE_PHY_CAP2_UL_MU_PARTIAL_MU_MIMO;
 	elem->phy_cap_info[2] |= c;
 

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

@@ -826,8 +826,8 @@ mt7915_mcu_sta_he_tlv(struct sk_buff *skb, struct ieee80211_sta *sta,
 }
 
 static void
-mt7915_mcu_sta_muru_tlv(struct sk_buff *skb, struct ieee80211_sta *sta,
-			struct ieee80211_vif *vif)
+mt7915_mcu_sta_muru_tlv(struct mt7915_dev *dev, struct sk_buff *skb,
+			struct ieee80211_sta *sta, struct ieee80211_vif *vif)
 {
 	struct mt7915_vif *mvif = (struct mt7915_vif *)vif->drv_priv;
 	struct ieee80211_he_cap_elem *elem = &sta->deflink.he_cap.he_cap_elem;
@@ -845,6 +845,7 @@ mt7915_mcu_sta_muru_tlv(struct sk_buff *skb, struct ieee80211_sta *sta,
 	muru->cfg.mimo_dl_en = mvif->cap.he_mu_ebfer ||
 			       mvif->cap.vht_mu_ebfer ||
 			       mvif->cap.vht_mu_ebfee;
+	if (!is_mt7915(&dev->mt76))
 		muru->cfg.mimo_ul_en = true;
 	muru->cfg.ofdma_dl_en = true;
 
@@ -1647,7 +1648,7 @@ int mt7915_mcu_add_sta(struct mt7915_dev *dev, struct ieee80211_vif *vif,
 		/* starec he */
 		mt7915_mcu_sta_he_tlv(skb, sta, vif);
 		/* starec muru */
-		mt7915_mcu_sta_muru_tlv(skb, sta, vif);
+		mt7915_mcu_sta_muru_tlv(dev, skb, sta, vif);
 		/* starec bfee */
 		mt7915_mcu_sta_bfee_tlv(dev, skb, vif, sta);
 	}