USB: fix suspend support for usblp

this implements suspend support for usblp. According to the CUPS people
ENODEV will make CUPS retry the job. Thus it is returned in the runtime
case. My printer survives suspend/resume cycles with it.

Signed-off-by: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>