drm/amd/smu: use AverageGfxclkFrequency* to replace previous GFX Curr Clock

Report current GFX clock also from average clock value as the original
CurrClock data is not valid/accurate any more as per FW team

Signed-off-by: Jane Jian <Jane.Jian@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>