dt-bindings: arm: rockchip: convert pmu.txt to YAML

Current dts files with 'pmu' nodes are manually verified.
In order to automate this process pmu.txt
has to be converted to yaml.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210417112952.8516-12-jbx6244@gmail.com


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