ARM: dts: rockchip: fix rk3288 watchdog irq

The watchdog irq is actually SPI 79, which translates to the original
111 in the manual where the SPI irqs start at 32.
The current dw_wdt driver does not use the irq at all, so this issue
never surfaced. Nevertheless fix this for a time we want to use the irq.

Fixes: 2ab557b7

 ("ARM: dts: rockchip: add core rk3288 dtsi")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Douglas Anderson <dianders@chromium.org>