S3C2412, S3C2443 and their derivatives contain a special software-reset
register in their system-controller.

Therefore register a restart handler for those.

Tested on a s3c2416-based board, s3c2412 compile-tested.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>