kernel-reboot-add-devm_register_reboot_notifier-fix

move `struct device' forward declaration to top-of-file

Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>