USB: removing ifdefed code from gl620a

as David has objected to the patch against the gl620a driver,
here's a patch implementing David' suggestion of removing the incomplete
ifdefed code from the gl620a driver.


Signed-off-by: Oliver Neukum <oliver@neukum.name>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>