net: mscc: ocelot: use DIV_ROUND_UP helper in ocelot_port_inject_frame

This looks a bit nicer than the open-coded "(x + 3) % 4" idiom.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mscc/ocelot_net.c

@@ -563,7 +563,7 @@ static int ocelot_port_xmit(struct sk_buff *skb, struct net_device *dev)
 		ocelot_write_rix(ocelot, (__force u32)cpu_to_be32(ifh[i]),
 				 QS_INJ_WR, grp);
 
-	count = (skb->len + 3) / 4;
+	count = DIV_ROUND_UP(skb->len, 4);
 	last = skb->len % 4;
 	for (i = 0; i < count; i++)
 		ocelot_write_rix(ocelot, ((u32 *)skb->data)[i], QS_INJ_WR, grp);