drm/amdgpu/vcn: Add VCN ras error query support

drm/amdgpu/vcn: Add VCN ras error query support

RAS error query support addition for VCN 2.6

V2: removed unused option and corrected comment format
Moved the register definition under header file

V3: poison query status check added.
Removed error query interface

V4: MMSCH poison check option removed, return true/false refactored.

Signed-off-by: Mohammad Zafar Ziya <Mohammadzafar.ziya@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Tao Zhou <tao.zhou1@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>