net/mlx5: Set devlink reload feature bit for supported devices only

Mulitport slave device doesn't support devlink reload, so instead of
complicating initialization flow with devlink_reload_enable() which
will be removed in next patch, don't set DEVLINK_F_RELOAD feature bit
for such devices.

This fixes an error when reload counters exposed (and equal zero) for
the mode that is not supported at all.

Fixes: d89ddaae ("net/mlx5: Disable devlink reload for multi port slave device")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>