net/mlx4: add consistency to copyright notices

net/mlx4: add consistency to copyright notices

Copyright lasts long enough not to require notices to be updated yearly.

The current approach of updating them occasionally while working on
unrelated tasks should be deprecated in favor of dedicated commits updating
all files at once when necessary.

Standardize on a single year per copyright owner.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>