cpufreq: intel_pstate: Rename two functions

Rename intel_cpufreq_adjust_hwp() and intel_cpufreq_adjust_perf_ctl()
to intel_cpufreq_hwp_update() and intel_cpufreq_perf_ctl_update(),
respectively, to avoid possible confusion with the ->adjist_perf()
callback function, intel_cpufreq_adjust_perf().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>