samples: net: mdns_responder: Increase interface name len for VLAN

In this sample, VLAN has longer interface name so increase it to max.

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

Author: jukkar

samples/net/mdns_responder/overlay-vlan.conf

@@ -32,3 +32,6 @@ CONFIG_NET_SAMPLE_IFACE3_VLAN_TAG=200
 # we do not run out of them.
 CONFIG_NET_MAX_CONTEXTS=10
 CONFIG_NET_MAX_CONN=10
+
+CONFIG_NET_INTERFACE_NAME=y
+CONFIG_NET_INTERFACE_NAME_LEN=15