net/ncsi: Enforce failover on link monitor timeout

The NCSI channel has been configured to provide service if its link
monitor timer is enabled, regardless of its state (inactive or active).
So the timeout event on the link monitor indicates the out-of-service
on that channel, for which a failover is needed.

This sets NCSI_DEV_RESHUFFLE flag to enforce failover on link monitor
timeout, regardless the channel's original state (inactive or active).
Also, the link is put into "down" state to give the failing channel
lowest priority when selecting for the active channel. The state of
failing channel should be set to active in order for deinitialization
and failover to be done.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>