Move devlink dev info callbacks, related drivers helpers functions and
other related code from leftover.c to dev.c. No functional change in
this patch.

Signed-off-by: Moshe Shemesh <moshe@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>