dt-bindings: soc: rockchip: convert grf.txt to YAML

dt-bindings: soc: rockchip: convert grf.txt to YAML

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

Most compatibility strings are in use with "simple-mfd" added.

Changed compatibles:
"rockchip,rk3066-grf", "syscon", "simple-mfd"
"rockchip,rk3188-grf", "syscon", "simple-mfd"

Add description already in use:
"rockchip,rv1108-pmugrf", "syscon"

Add new descriptions for:
"rockchip,rk3568-grf", "syscon", "simple-mfd"
"rockchip,rk3568-pmugrf", "syscon", "simple-mfd"

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210512122346.9463-3-jbx6244@gmail.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>