This change enables the sunvdc driver to reconnect and recover if a vds
service domain is disconnected or bounced.

By default, it will wait indefinitely for the service domain to become
available again, but will honor a non-zero vdc-timout md property if one
is set. If a timeout is reached, any in-progress I/O's are completed
with -EIO.
Signed-off-by: NDwight Engen <dwight.engen@oracle.com>
Reviewed-by: NChris Hyser <chris.hyser@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>