drm/amdgpu: mark a bunch of module parameters unsafe

We sometimes have people trying to use debugging options in production
environments.

Mark options only meant to be used for debugging as unsafe so that the
kernel is tainted when they are used.

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Felix Kuehling <felix.kuehling@amd.com>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>