Revert "cpufreq: intel_pstate: Avoid calculation for max/min"

Revert commit 4ef45148 (cpufreq: intel_pstate: Avoid calculation for
max/min) as it depends on commit 37afb000

 (cpufreq: intel_pstate: Use
ACPI perf configuration) that causes problems to happen and needs to be
reverted.

Conflicts:
	drivers/cpufreq/intel_pstate.c

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>