drm/amdgpu/sriov: Use VF-accessible register for gpu_clock_count

Navi12 VK CTS subtest timestamp.calibrated.dev_domain_test failed
because mmRLC_CAPTURE_GPU_CLOCK_COUNT register cannot be
written in VF due to security policy.

Solution: use a VF-accessible timestamp register pair
mmGOLDEN_TSC_COUNT_LOWER/UPPER for SRIOV case.

v2: according to Deucher Alexander's advice, switch to
mmGOLDEN_TSC_COUNT_LOWER/UPPER for both bare metal and SRIOV.

Signed-off-by: jianzh <Jiange.Zhao@amd.com>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>