We have to use the fw_device.generation here, not the fw_card.generation,
because the generation must never be newer than the node ID when we emit
a transaction.  This cannot be guaranteed with fw_card.generation.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

Verified in concert with subsequent memory barriers patch to fix 'giving
up on config rom' issues on multiple system and drive combinations that
were previously affected.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>