ARM: dts: s3c64xx: Fix infinite interrupt in soft mode

In soft (no-reboot) mode, the driver self-pings watchdog upon expiration
of an interrupt.  The interrupt has to be cleared, because otherwise
system enters infinite interrupt handling loop.

Use a samsung,s3c6410-wdt compatible to select appropriate quirk for
clearing the watchdog interrupt.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>