Currently there is no way for pf to know if a vf device is
alive or not, so PF does not know which vf to notify when
reset happens, or which vf's mtu is invalid when vf and pf
share the same hardware mtu setting.

This patch adds vport alive state checking support, in order
to support the above scenario.
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Jian Shen <shenjian15@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>