drm/amd/pm: correct the fan speed retrieving in PWM for some SMU13 asics

For SMU 13.0.0 and 13.0.7, the output from PMFW is in percent. Driver
need to convert that into correct PMW(255) based.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>