dt-bindings: Drop unnecessary quotes on keys

The yamllint quoted-strings check wasn't checking keys for quotes, but
support for checking keys was added in 1.34 release. Fix all the errors
found when enabling the check.

Clean-up the xilinx-versal-cpm formatting while we're here.

Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20240426202239.2837516-1-robh@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>