cpupower: Don't try to read frequency from hardware when kernel uses aperfmperf

cpupower: Don't try to read frequency from hardware when kernel uses aperfmperf

When the amd-pstate is in use frequency is set by the hardware and
measured by the kernel through using the aperf and mperf registers.

There is no direct call to the hardware to indicate current frequency.

Detect that this feature is in use and skip the check.

Link: https://lore.kernel.org/r/20241218191144.3440854-5-superm1@kernel.org
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>