Actually loady command uses '-g' option for Y-Modem/G mode
selection; see loady() function:

    while ((opt = getopt(argc, argv, "b:t:g")) > 0) {
        switch (opt) {
    ...
        case 'g':
            is_ymodemg = 1;
            break;

By mistake help message show '-y' option for Y-Modem/G mode
selection.

This patch fixes the problem.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>