drm/amdgpu/powerplay: using the FCLK DPM table to set the MCLK

1.Using the FCLK DPM table to set the MCLK for DPM states consist of
three entities:
 FCLK
 UCLK
 MEMCLK
All these three clk change together, MEMCLK from FCLK, so use the fclk
frequency.
2.we should show the current working clock freqency from clock table metric

Signed-off-by: Yuxian Dai <Yuxian.Dai@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Kevin Wang <Kevin1.Wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org