rtl8180: be paranoid in stopping unused queues.

HW should never attempt to perform DMA for unused queues.
For rtl8187se this is ensured by setting a dedicated register at
init time, before enabling TX.

In rtl8180/5 the register is only written at the first TX (because
in rtl8180/5 it serves also to kick DMA for used queues).
This should be enough, but it's worth to add a register write at
init time, before enabling TX.
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtl818x/rtl8180/dev.c

@@ -910,7 +910,10 @@ static int rtl8180_init_hw(struct ieee80211_hw *dev)
 		reg32 &= 0x00ffff00;
 		reg32 |= 0xb8000054;
 		rtl818x_iowrite32(priv, &priv->map->RF_PARA, reg32);
-	}
+	} else
+		/* stop unused queus (no dma alloc) */
+		rtl818x_iowrite8(priv, &priv->map->TX_DMA_POLLING,
+			    (1<<1) | (1<<2));
 
 	priv->rf->init(dev);