mt76x2: remove leftover mt76u_buf data structure in mt76x2_mcu

Remove unused usb buffer in mt76x2_mcu data structure
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76x2.h

@@ -52,7 +52,6 @@ struct mt76x2_mcu {
 
 	wait_queue_head_t wait;
 	struct sk_buff_head res_q;
-	struct mt76u_buf res_u;
 
 	u32 msg_seq;
 };