firewire: fw-ohci: check for misconfigured bus (phyID == 63)

Check NodeID.nodeNumber as per OHCI 1.1 clause 7.2.3.2.  See also IEEE
1394a table 5B-1.

Also, demote the "node ID not valid" message from error to notification
as it is not an error condition.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>