This patchset was originally done by eightdot <gituser@eightdot.eu> by
manually forward-porting parts of the changes done by Bert Vermeulen (see
previous commits), but then heavily modified by Uwe Hermann to be based on
top off the (git-)rebased patches from Bert Vermeulen instead.
Note: This initial DSLogic code is *not* yet in a working or usable
state. It should be considered as a basis for further work only, for now.
Previously, sdi->index was used to tell several identical fx2lafw-compatible
devices apart. This was a bit of a hack, so this patch makes it use physical
device connections instead. They're guaranteed to remain the same even if
the USB device reconnects.