rt2x00: Disable RX aggregation for rt2800usb

RX aggregation is a way to receive multiple 802.11 frames in one RX buffer.
However, we don't know yet how to handle this case in rt2800usb_fill_rxdone
and this has probably no impact on RX performance as well, so we disable it
Signed-off-by: Benoit Papillault <benoit.papillault@free.fr>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <ivdoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2800usb.c

@@ -295,9 +295,7 @@ static int rt2800usb_enable_radio(struct rt2x00_dev *rt2x00dev)
 
 	rt2800_register_read(rt2x00dev, USB_DMA_CFG, &reg);
 	rt2x00_set_field32(&reg, USB_DMA_CFG_PHY_CLEAR, 0);
-	/* Don't use bulk in aggregation when working with USB 1.1 */
-	rt2x00_set_field32(&reg, USB_DMA_CFG_RX_BULK_AGG_EN,
-			   (rt2x00dev->rx->usb_maxpacket == 512));
+	rt2x00_set_field32(&reg, USB_DMA_CFG_RX_BULK_AGG_EN, 0);
 	rt2x00_set_field32(&reg, USB_DMA_CFG_RX_BULK_AGG_TIMEOUT, 128);
 	/*
 	 * Total room for RX frames in kilobytes, PBF might still exceed