RDMA/rxe: Remove deliver net device event

Since the netdev events of link status is now handled in ib_core,
remove the related code in drivers.

In addition, remove the setting of port->attr.state in rxe_port_up()
and rxe_port_down(), as it is only used in rxe_query_port(), and it
can be replaced by ib_get_curr_port_state().

Signed-off-by: Yuyu Li <liyuyu6@huawei.com>
Signed-off-by: Junxian Huang <huangjunxian6@hisilicon.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>