mt76: mt7915: disable OFDMA/MU-MIMO UL

The feature is not ready in firmware yet, and it leads to hangs
Signed-off-by: Felix Fietkau <nbd@nbd.name>

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

@@ -1552,9 +1552,7 @@ mt7915_mcu_sta_muru_tlv(struct sk_buff *skb, struct ieee80211_sta *sta)
 
 	muru = (struct sta_rec_muru *)tlv;
 	muru->cfg.ofdma_dl_en = true;
-	muru->cfg.ofdma_ul_en = true;
 	muru->cfg.mimo_dl_en = true;
-	muru->cfg.mimo_ul_en = true;
 
 	muru->ofdma_dl.punc_pream_rx =
 		HE_PHY(CAP1_PREAMBLE_PUNC_RX_MASK, elem->phy_cap_info[1]);