net: pxa168_eth: use {readl|writel}_relaxed instead of readl/writel

Since appropriate memory barriers are already there, use the relaxed
version to improve performance a bit.
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/pxa168_eth.c

@@ -286,12 +286,12 @@ static int pxa168_eth_stop(struct net_device *dev);
 
 static inline u32 rdl(struct pxa168_eth_private *pep, int offset)
 {
-	return readl(pep->base + offset);
+	return readl_relaxed(pep->base + offset);
 }
 
 static inline void wrl(struct pxa168_eth_private *pep, int offset, u32 data)
 {
-	writel(data, pep->base + offset);
+	writel_relaxed(data, pep->base + offset);
 }
 
 static void abort_dma(struct pxa168_eth_private *pep)