uboot-imx

dm: sysreset: add watchdog-reboot driver

Add a new sysreset driver that uses the recently added watchdog support.
It performs a full SoC reset by calling wdt_expire_now op.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>