Staging: vt6656: struct usb_driver cleanup

Code cleanup following other USB drivers:
	- Renamed driver struct and callbacks to vt6656_*
	- Added __init/__exit like directives
	- Resolved checkpatch.pl findings on those lines

Signed-off-by: Andres More <more.andres@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>