cac_start: add TODO to fully support optional methods arg

src/cntlr_commands_impl.c

@@ -578,6 +578,9 @@ int COMMAND(cac_start)(void *priv, void *args, void *out)
 		channel = (uint8_t)blobmsg_get_u32(tb[CAC_START_ATTR_CHANNEL]);
 
 	if (tb[CAC_START_ATTR_METHOD]) {
+		/* TODO: if method is not provided then lookup CAC capability
+		 * of the passed agent node as exchange via AP Capability
+		 */
 		method  = (uint8_t)blobmsg_get_u32(tb[CAC_START_ATTR_METHOD]);
 		if (method > 3)
 			return -EINVAL;