Introduce new devlink call to set feature mask to control devlink
behavior during device initialization phase after devlink_alloc()
is already called.

This allows us to set reload ops based on device property which
is not known at the beginning of driver initialization.

For the sake of simplicity, this API lacks any type of locking and
needs to be called before devlink_register() to make sure that no
parallel access to the ops is possible at this stage.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>