mailmap: change email for Ricardo Ribalda

Modify  emails to ribalda@kernel.org and unify my surname in all the
files.

Signed-off-by: Ricardo Ribalda <ribalda@kernel.org>
Link: https://lore.kernel.org/r/20200430135224.362700-1-ricardo@ribalda.com


Signed-off-by: Jonathan Corbet <corbet@lwn.net>