cpufreq: do not open-code of_phandle_args_equal()

Use newly added of_phandle_args_equal() helper to compare two
of_phandle_args.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240129115216.96479-3-krzysztof.kozlowski@linaro.org


Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>