mt76: fix corrupted software generated tx CCMP PN

Since ccmp_pn is u8 *, the second half needs to start at array index 4
instead of 0. Fixes a connection stall after a certain amount of traffic

Fixes: 2340523646 ("mt76: fix transmission of encrypted management frames")
Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76x02_mac.c

@@ -314,7 +314,7 @@ void mt76x02_mac_write_txwi(struct mt76x02_dev *dev, struct mt76x02_txwi *txwi,
 		ccmp_pn[6] = pn >> 32;
 		ccmp_pn[7] = pn >> 40;
 		txwi->iv = *((__le32 *)&ccmp_pn[0]);
-		txwi->eiv = *((__le32 *)&ccmp_pn[1]);
+		txwi->eiv = *((__le32 *)&ccmp_pn[4]);
 	}
 
 	spin_lock_bh(&dev->mt76.lock);