firewire: Schedule topology work before calling driver update functions.

This prevents superfluous bus traffic as fw-sbp2 logs in only to
get kicked off the device by another bus reset as the driver core
does bus management.  Scheduling it this way lets the driver core
finish bus management before higher level drivers get the update
callback.

Signed-off-by: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>