HID: fix reference count leak hidraw

The hidraw subsystem has a bug that prevents the close syscall from ever
reaching the low level driver, leading to a resource leak. Fix by replacing
postdecrement with predecrement.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>