drivers: eth: native_sim: Fix error output when creating interface

The return value already contains the errno so use it when printing
the error message.

Signed-off-by: Jukka Rissanen <[email protected]>

Author: jukkar

drivers/ethernet/eth_native_posix.c

@@ -358,7 +358,8 @@ static void eth_iface_init(struct net_if *iface)
 
 	ctx->dev_fd = eth_iface_create(CONFIG_ETH_NATIVE_POSIX_DEV_NAME, ctx->if_name, false);
 	if (ctx->dev_fd < 0) {
-		LOG_ERR("Cannot create %s (%d)", ctx->if_name, -errno);
+		LOG_ERR("Cannot create %s (%d/%s)", ctx->if_name, ctx->dev_fd,
+			strerror(-ctx->dev_fd));
 	} else {
 		/* Create a thread that will handle incoming data from host */
 		create_rx_handler(ctx);