ravb: fix race updating TCCR

The TCCR.TSRQn bit may get clearead after TCCR gets read, so that TCCR write
would get skipped. We don't need to check this bit before setting.
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/renesas/ravb_main.c

@@ -1275,7 +1275,6 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	u32 dma_addr;
 	void *buffer;
 	u32 entry;
-	u32 tccr;
 
 	spin_lock_irqsave(&priv->lock, flags);
 	if (priv->cur_tx[q] - priv->dirty_tx[q] >= priv->num_tx_ring[q]) {
@@ -1324,9 +1323,7 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	dma_wmb();
 	desc->die_dt = DT_FSINGLE;
 
-	tccr = ravb_read(ndev, TCCR);
-	if (!(tccr & (TCCR_TSRQ0 << q)))
-		ravb_write(ndev, tccr | (TCCR_TSRQ0 << q), TCCR);
+	ravb_write(ndev, ravb_read(ndev, TCCR) | (TCCR_TSRQ0 << q), TCCR);
 
 	priv->cur_tx[q]++;
 	if (priv->cur_tx[q] - priv->dirty_tx[q] >= priv->num_tx_ring[q] &&