USB: Remove unsupported usb gadget drivers

A bunch of USB gadget drivers where never ported from the linux 2.4
series to 2.6 kernels. However there's some code still in the tree for
them which isn't used and is probably untested for ages.

As the chance of these drivers being forward ported is probably quite
small now it might be time to get rid of them.

Signed-off-by: Christoph Egger <siccegge@stud.informatik.uni-erlangen.de>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>