sandbox: net: Correct name copy in eth_raw_bus_post_bind()

We cannot be sure that the interface name takes up the full length of the
space available to it. Use strcpy() instead of memcpy() in this case. This
corrects a valgrind warning.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/net/sandbox-raw-bus.c b/drivers/net/sandbox-raw-bus.c
index 76d65af..0086f25 100644
--- a/drivers/net/sandbox-raw-bus.c
+++ b/drivers/net/sandbox-raw-bus.c
@@ -42,7 +42,7 @@
 		device_probe(child);
 		priv = dev_get_priv(child);
 		if (priv) {
-			memcpy(priv->host_ifname, i->if_name, IFNAMSIZ);
+			strcpy(priv->host_ifname, i->if_name);
 			priv->host_ifindex = i->if_index;
 			priv->local = local;
 		}