cpufreq: intel_pstate: Take CPUFREQ_GOV_STRICT_TARGET into account

Make intel_pstate take the new CPUFREQ_GOV_STRICT_TARGET governor
flag into account when it operates in the passive mode with HWP
enabled, so as to fix the "powersave" governor behavior in that
case (currently, HWP is allowed to scale the performance all the
way up to the policy max limit when the "powersave" governor is
used, but it should be constrained to the policy min limit then).

Fixes: f6ebbcf0 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+: 9a2a9ebc cpufreq: Introduce governor flags
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+: 218f6687 cpufreq: Introduce CPUFREQ_GOV_STRICT_TARGET
Cc: 5.9+ <stable@vger.kernel.org> # 5.9+: ea9364bb cpufreq: Add strict_target to struct cpufreq_policy