cpufreq: apple-soc: Drop setting the PS2 field on M2+

Newer device do not use this. It is not known what this field does,
but change the behavior to be same as macOS to be safe.

Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Nick Chan <towinchenmi@gmail.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>