[U-Boot] [RFC PATCH 39/44] mkimage: Add -c option to specify a comment for key signing

[Marek Vasut]

Dear Simon Glass,

> When signing an image, it is useful to add some details about which tool
> or person is authorising the signing. Add a comment field which can take
> care of miscellaneous requirements.
> 
> Signed-off-by: Simon Glass <sjg at chromium.org>

Reviewed-by: Marek Vasut <marex at denx.de>

Best regards,
Marek Vasut