samples: lwm2m: allow longer endpoint names

Server might return the endpoint name in a registration reply. Default
max allowed endpoint name is only 12 characters.

Signed-off-by: Veijo Pesonen <[email protected]>

Author: Veijo Pesonen

samples/net/lwm2m_client/prj.conf

@@ -35,3 +35,7 @@ CONFIG_NET_CONFIG_MY_IPV6_ADDR="2001:db8::1"
 CONFIG_NET_CONFIG_PEER_IPV6_ADDR="2001:db8::2"
 CONFIG_NET_CONFIG_MY_IPV4_ADDR="192.0.2.1"
 CONFIG_NET_CONFIG_PEER_IPV4_ADDR="192.0.2.2"
+
+# Longer endpoint name might be returned in a registration reply
+CONFIG_COAP_EXTENDED_OPTIONS_LEN=y
+CONFIG_COAP_EXTENDED_OPTIONS_LEN_VALUE=40