p54pci: fix -Wunused-but-set-variable warnings

p54pci.c: In function ‘p54p_tx’:
p54pci.c:334:6: warning: variable ‘device_idx’ set but not used
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/p54/p54pci.c

@@ -331,10 +331,9 @@ static void p54p_tx(struct ieee80211_hw *dev, struct sk_buff *skb)
 	struct p54p_ring_control *ring_control = priv->ring_control;
 	struct p54p_desc *desc;
 	dma_addr_t mapping;
-	u32 device_idx, idx, i;
+	u32 idx, i;
 
 	spin_lock_irqsave(&priv->lock, flags);
-	device_idx = le32_to_cpu(ring_control->device_idx[1]);
 	idx = le32_to_cpu(ring_control->host_idx[1]);
 	i = idx % ARRAY_SIZE(ring_control->tx_data);