drm/amdgpu: Initialize sdma v4_4_2 ras function

Initialize sdma v4_4_2 ras function and interrupt
handler.

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