firewire: Don't set card->irm_node before we have a new valid topology.

In case the topology build fails, we want to retain the old topology
info until another reset finishes and results in a valid new tree.  If
we clear card->irm_node to NULL and the topology build fails, we end up
dereferencing a NULL pointer in a few places.

Signed-off-by: Kristian Høgsberg <[email protected]>
Signed-off-by: Stefan Richter <[email protected]>
1 file changed