sh_eth: use ETH_ZLEN instead of home-grown #define

The driver #define's and uses ETHERSMALL macro for the minimum Ethernet frame
size for which we have a standard macro ETH_ZLEN.  Use the latter  instead of
the home-grown one.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/renesas/sh_eth.h b/drivers/net/ethernet/renesas/sh_eth.h
index 6075915..d55e37c 100644
--- a/drivers/net/ethernet/renesas/sh_eth.h
+++ b/drivers/net/ethernet/renesas/sh_eth.h
@@ -27,8 +27,7 @@
 #define RX_RING_MIN	64
 #define TX_RING_MAX	1024
 #define RX_RING_MAX	1024
-#define ETHERSMALL		60
-#define PKT_BUF_SZ		1538
+#define PKT_BUF_SZ	1538
 #define SH_ETH_TSU_TIMEOUT_MS	500
 #define SH_ETH_TSU_CAM_ENTRIES	32