The instant retrieved gfxclk value should be 0 in gfxoff state.
This can be fetched with gfxoff enabled.
Signed-off-by: Kenneth Feng <kenneth.feng@amd.com>
Reviewed-by: Likun Gao <Likun.Gao@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>