cpufreq: intel_pstate: Update the maximum CPU frequency consistently

There are 3 places at which the maximum CPU frequency may change,
store_no_turbo(), intel_pstate_update_limits() (when called by the
cpufreq core) and intel_pstate_notify_work() (when handling a HWP
change notification).  Currently, cpuinfo.max_freq is only updated by
store_no_turbo() and intel_pstate_notify_work(), although it principle
it may be necessary to update it in intel_pstate_update_limits() either.

Make all of them mutually consistent.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>