drm/amdgpu: fix parser init error path to avoid crash in parser fini

If we don't reset the chunk info in the error path, the subsequent
fini path will double free.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>