net/ncsi: Don't take any action on HNCDSC AEN

The current HNCDSC handler takes the status flag from the AEN packet and
will update or change the current channel based on this flag and the
current channel status.

However the flag from the HNCDSC packet merely represents the host link
state. While the state of the host interface is potentially interesting
information it should not affect the state of the NCSI link. Indeed the
NCSI specification makes no mention of any recommended action related to
the host network controller driver state.

Update the HNCDSC handler to record the host network driver status but
take no other action.

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: David S. Miller <davem@davemloft.net>