net: Increase ethernet name string size to 20 chars

The 16 char ethernet name size is inadequate to hold the name of ethernet
name "DPMAC17@rgmii-id", which is a valid name in LX2160AQDS/LX2160ARDB.

Therefore, increase the name string size to 20 chars.

Reported-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Suggested-by: Ioana Ciocoi Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: Pankaj Bansal <pankaj.bansal@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>

include/net.h

@@ -164,7 +164,7 @@ void eth_halt_state_only(void); /* Set passive state */
 
 #ifndef CONFIG_DM_ETH
 struct eth_device {
-#define ETH_NAME_LEN 16
+#define ETH_NAME_LEN 20
 	char name[ETH_NAME_LEN];
 	unsigned char enetaddr[ARP_HLEN];
 	phys_addr_t iobase;