ieee1394: update URLs in debugging-via-ohci1394.txt

Update URLs of the userspace tools to use ohci1394_dma=early for
debugging.

Seems the address ftp://ftp.suse.de/private/bk/firewire/tools/* is not
very helpful.  After a quick search, seems this was talked about:
http://www.mail-archive.com/kgdb-bugreport@lists.sourceforge.net/msg02761.html
(can't find the original thread).

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>