hisax: update hfc_usb driver

This fixes handling of USB ISO completion error -EXDEV and includes
several other changes to current CVS version at isdn4linux.de (changes
in debug flags, style of code remarks, etc)

Signed-off-by: Martin Bachem <info@colognechip.com>
Acked-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>