sound: q6adm: Redirect default and custom topologies to NULL topology…

… for legacy, low latency, and ULLP PCM playback

Instead of redirecting to default COPP which is equivalent to stereo speaker COPP topology, let's just nullify it to devoid low latency playback of any post-DSP processing unless a specific ADM topology is intentionally set by the routing driver that is not the default nor an external effect.

Let us also include legacy PCM playback to this patch to completely disable post-DSP processing as a whole.

[Adjusted to techpack 4.14]
Change-Id: I88f6eac77cdd5a158faa2356a371a087a3a41869
Signed-off-by: minaripenguin <minaripenguin@users.noreply.github.com>