Currently, There is a low probability that pf mtu configuration fails, but
the information in logs is insufficient for problem locating when the VF
mtu value is illegally modified.

So record the vf index and vf mtu value at the failure scenario.
Signed-off-by: Jie Wang <wangjie125@huawei.com>
Signed-off-by: Guangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>