Fix bogus warning in sysdev_driver_register()

        if ((drv->entry.next != drv->entry.prev) ||
            (drv->entry.next != NULL)) {

warns list_empty(&drv->entry).

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Greg KH <gregkh@suse.de>
Cc: Len Brown <lenb@kernel.org>
[ Version 2 totally redone based on suggestions from Linus & Greg ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>