ASoC: dt-bindings: Move port/ports properties out of audio-graph-port.yaml

ASoC: dt-bindings: Move port/ports properties out of audio-graph-port.yaml

Users of the audio-graph-port schema need to define how many ports
and what each port is, so they need to define 'ports' and/or 'port'
anyways. Let's drop 'ports' and 'port' from the schema and adjust users
to reference audio-graph-port.yaml from a port property.

Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Lubomir Rintel <lkundrak@v3.sk>
Cc: Sameer Pujar <spujar@nvidia.com>
Cc: alsa-devel@alsa-project.org
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210331142748.2163272-2-robh@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>