net: hns3: add a check before PF inform VF to reset

net: hns3: add a check before PF inform VF to reset

BugLink: https://launchpad.net/bugs/1867586
When setting VF's MAC from PF, if the VF driver not loaded, the
firmware will return error to PF.

So PF should check whether VF is alive before sending message to
VF when setting VF's MAC.

Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: Huazhong Tan <tanhuazhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 9091367037d3e6db590d9f8cd9a163336665ef27)
Signed-off-by: Ike Panhc <ike.pan@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>