greybus: interface: Prefix DDBL1 attributes with ddbl1_ instead of unipro_

The Device descriptor block Level 1 (DDBL1) attributes are specified by
the MIPI standard and prefixing them with 'unipro_' isn't the best thing
to do. They should be prefixed with DDBL1 instead.

To make it more readable/clear:
- rename macros and variable by prefixing them with ddbl1_.
- write full names for mfg and prod ids as manufacturer and product ids.
- replace mfg (manufacturing) with mfr (manufacturer)

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>