samples: net: mqtt: Align with SFM_CREATE_STATE API changes

From the upstream migration guide:

The SMF_CREATE_STATE macro now always takes 5 arguments. The amount
of arguments is now independent of the values of
CONFIG_SMF_ANCESTOR_SUPPORT and CONFIG_SMF_INITIAL_TRANSITION.
If the additional arguments are not used, they have to be set to NULL

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>

Author: rlubos

samples/net/mqtt/src/modules/transport/transport.c

@@ -299,8 +299,10 @@ static void connected_exit(void *o)
 
 /* Construct state table */
 static const struct smf_state state[] = {
-	[MQTT_DISCONNECTED] = SMF_CREATE_STATE(disconnected_entry, disconnected_run, NULL),
-	[MQTT_CONNECTED] = SMF_CREATE_STATE(connected_entry, connected_run, connected_exit),
+	[MQTT_DISCONNECTED] = SMF_CREATE_STATE(disconnected_entry, disconnected_run, NULL,
+					       NULL, NULL),
+	[MQTT_CONNECTED] = SMF_CREATE_STATE(connected_entry, connected_run, connected_exit,
+					    NULL, NULL),
 };
 
 static void transport_task(void)