cpufreq: Drop cpufreq_cpu_acquire() and cpufreq_cpu_release()

Since cpufreq_cpu_acquire() and cpufreq_cpu_release() have no more
users in the tree, remove them.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://patch.msgid.link/3880470.kQq0lBPeGt@rjwysocki.net