net: fec: use swab32s() instead of cpu_to_be32()

when swap_buffer() is being called, we know for sure, that we need to
byte swap the data. Furthermore, this function is called for swapping
data in both directions. Thus cpu_to_be32() is semantically not
correct for all use cases. Use swab32s() to reflect this.
Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/fec_main.c

@@ -293,7 +293,7 @@ static void *swap_buffer(void *bufaddr, int len)
 	unsigned int *buf = bufaddr;
 
 	for (i = 0; i < DIV_ROUND_UP(len, 4); i++, buf++)
-		*buf = cpu_to_be32(*buf);
+		swab32s(buf);
 
 	return bufaddr;
 }