cmd: fix long text for sound command

Make it clear that if only 1 parameter is provided this is the duration.

The ISO symbol for hertz is Hz.

Fixes: c0c88533fffd ("Sound: Add command for audio playback")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/cmd/sound.c b/cmd/sound.c
index f82f2aa..20ac3f7 100644 (file)
--- a/cmd/sound.c
+++ b/cmd/sound.c
@@ -86,5 +86,5 @@ U_BOOT_CMD(
        sound, 4, 1, do_sound,
        "sound sub-system",
        "init - initialise the sound driver\n"
-       "sound play [len] [freq] - play a sound for len ms at freq hz\n"
+       "sound play [len [freq]] - play a sound for len ms at freq Hz\n"
 );