ARM: dts: rockchip: add new watchdog compatible to rv1108.dtsi

ARM: dts: rockchip: add new watchdog compatible to rv1108.dtsi

The watchdog compatible strings are suppose to be SoC orientated.
In the more recently added Rockchip rv1108.dtsi file only
the fallback string "snps,dw-wdt" is used, so add the new
compatible string:

"rockchip,rv1108-wdt", "snps,dw-wdt"

make ARCH=arm dtbs_check
DT_SCHEMA_FILES=Documentation/devicetree/bindings/watchdog/snps,dw-wdt.yaml

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Link: https://lore.kernel.org/r/20201218120534.13788-2-jbx6244@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>