be2net: log link status

The driver unlike other drivers does not log link state changes. It's
better for an user when asynchronous link states are logged to the system
log.

v3: Changes from v2 discarded as "not necessary"

Cc: Sathya Perla <sathya.perla@emulex.com>
Cc: Subbu Seetharaman <subbu.seetharaman@emulex.com>
Cc: Ajit Khaparde <ajit.khaparde@emulex.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>