drm/amdgpu: always enable shadow BOs v2

Even when GPU recovery is disabled we could run into a manually
triggered recovery.

v2: keep accidental removed comments

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Emily Deng <Emily.Deng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>