Fix unchecked MSR access error for processors with no HWP support. On
such processors, maximum frequency can be changed by the system firmware
using ACPI event ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED. This results
in accessing HWP MSR 0x771.
HWP MSR 0x771 can be only read on a CPU which supports HWP and enabled.
Hence intel_pstate_get_hwp_cap() can only be called when hwp_active is
true.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Closes: https://lore.kernel.org/linux-pm/20240529155740.Hq2Hw7be@linutronix.de/ Fixes: e8217b4bece3 ("cpufreq: intel_pstate: Update the maximum CPU frequency consistently") Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>