While there:
- check the number of command parameters;
- add the mandatory 'usage' field.
Change-Id: I7cd16f049753caedf19f313f7dc84be98efdba42
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7497
Tested-by: jenkins