qed/qede: make devlink survive recovery

Devlink instance lifecycle was linked to qed_dev object,
that caused devlink to be recreated on each recovery.

Changing it by making higher level driver (qede) responsible for its
life. This way devlink now survives recoveries.

qede now stores devlink structure pointer as a part of its device
object, devlink private data contains a linkage structure,
qed_devlink.

Signed-off-by: Igor Russkikh <irusskikh@marvell.com>
Signed-off-by: Alexander Lobakin <alobakin@marvell.com>
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>