devlink: Delete not-used single parameter notification APIs

There is no need in specific devlink_param_*publish(), because same
output can be achieved by using devlink_params_*publish() in correct
places.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>