[cmdline] Generate command option help text automatically

Generate the command option help text automatically from the list of
defined options.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/hci/commands/lotest_cmd.c

@@ -50,8 +50,7 @@ static struct option_descriptor lotest_opts[] = {
 /** "lotest" command descriptor */
 static struct command_descriptor lotest_cmd =
 	COMMAND_DESC ( struct lotest_options, lotest_opts, 2, 2,
-		       "[--mtu <mtu>] <sending interface> "
-		       "<receiving interface>" );
+		       "<sending interface> <receiving interface>" );
 
 /**
  * "lotest" command