add option for raw output

[ensc]

For later analysis or to copy data like keys from OTP, it is useful to
output the read data directly as binary.

Patch adds '-r' option to enable this behavior.

[ukleinek]

Thanks for your patch. I would prefer an implementation of a memcpy command instead.
If you want to work on that, please take care to use a consistent style for line indention to match the style that is already used.
BR

[a3f]

For reference, here's the documentation of barebox's memcpy command: https://www.barebox.org/doc/latest/commands/mem/memcpy.html