jcat.c: Reformat help/usage output to be compatible with help2man.

Signed-off-by: Alexander GQ Gerasiov <gq@cs.msu.su>

Gbp-Pq: Name 0019-jcat.c-Reformat-help-usage-output-to-be-compatible-w.patch

j1939cat.c

@@ -84,7 +84,7 @@ static const char help_msg[] =
 	"\n"
 	;
 
-static const char optstring[] = "?i:vs:rp:P:R:";
+static const char optstring[] = "?hi:vs:rp:P:R:";
 
 
 static void j1939cat_init_sockaddr_can(struct sockaddr_can *sac)
@@ -617,6 +617,7 @@ static int j1939cat_parse_args(struct j1939cat_priv *priv, int argc, char *argv[
 		if (priv->repeat < 1)
 			err(EXIT_FAILURE, "send/repeat count can't be less then 1\n");
 		break;
+	case 'h': /*fallthrough*/
 	default:
 		fputs(help_msg, stderr);
 		return EXIT_FAILURE;