dt-bindings: clock: convert rockchip,px30-cru.txt to YAML

Convert rockchip,px30-cru.txt to YAML.

Changes against original bindings:
  Use compatible string: "rockchip,px30-pmucru"

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220330103923.11063-1-jbx6244@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>