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
--- a/cmd/sound.c
+++ b/cmd/sound.c
@@ -86,5 +86,5 @@
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"
);