mlxsw: spectrum: Pass mlxsw_core as arg of mlxsw_sp_kvdl_resources_register()

Pass struct mlxsw_core instead of devlink since it is nicer within mlxsw
code and we need both structs in mlxsw_sp_kvdl_resources_register()
anyway.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>