ASoC: Add json-schema documentation for sound-name-prefix

The 'sound-name-prefix' is used to prepend suitable strings to a
component widgets or controls. This is helpful when there are
multiple instances of the same component. Add relevant json-schema
and is inspired from sound-name-prefix.txt documentation.
Signed-off-by: Sameer Pujar <spujar@nvidia.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Rob Herring <robh+dt@kernel.org>
Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1630686919-19495-2-git-send-email-spujar@nvidia.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/name-prefix.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/name-prefix.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Component sound name prefix
+
+maintainers:
+  - Jerome Brunet <jbrunet@baylibre.com>
+
+properties:
+  sound-name-prefix:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: |
+      Card implementing the routing property define the connection between
+      audio components as list of string pair. Component using the same
+      sink/source names may use this property to prepend the name of their
+      sinks/sources with the provided string.
+
+additionalProperties: true