dt-bindings: soc: google: exynos-sysreg: add dedicated SYSREG compatibles to GS101

GS101 has three different SYSREG controllers, add dedicated
compatibles for them to the documentation.

Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Link: https://lore.kernel.org/r/20231209233106.147416-4-peter.griffin@linaro.org


[krzysztof: move Google entries to existing enum]
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>