dt-bindings: soc: microchip: sparx5-cpu-syscon: Move to dedicated schema

dt-bindings: soc: microchip: sparx5-cpu-syscon: Move to dedicated schema

microchip,sparx5-cpu-syscon is not a simple syscon device - it has
children and implements simple-mfd compatible - thus it should be fully
documented in its own binding.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240626-dt-bindings-mfd-syscon-split-v3-4-3409903bb99b@linaro.org
Signed-off-by: Lee Jones <lee@kernel.org>