drm/amdgpu: update RAS sequence to parse TA flags

RAS TA shall notify driver with flags of error specifics

Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: John Clements <john.clements@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>