devlink: remove netlink small_ops

All commands are now covered by generated split_ops. Remove the
small_ops entirely alongside with unified devlink netlink policy array.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20231021112711.660606-11-jiri@resnulli.usSigned-off-by: Jakub Kicinski <kuba@kernel.org>