usbtouchscreen: version 0.4

changes over 0.3:
- some more eGalax device IDs (from eGalax driver/spec)
- return the error code in probe()
- 3M/MTouch init fixes, tested by Don Alexander
- eGalax fixes for bugs in multi-packet handling, spottet by Pieter Grimmerink
- support for some eTurboTouch devices, mostly by Pieter Grimmerink
- support for Gunze AHL61 controller (untested, but simple enough)

Signed-off-by: Daniel Ritz <daniel.ritz@gmx.ch>
Cc: Pieter Grimmerink <p.grimmerink@inepro.com>
Cc: Don Alexander <debug@roosoft.ltd.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>