ASoC: dt-bindings: renesas,rsnd: remove post-init-providers property

commit f8da001ae7a ("ASoC: audio-graph-card2: Purge absent supplies for
device tree nodes") marks multi/dpcm/c2c nodes as no suppliers. We no
longer need to use post-init-providers property to break fw_devlink cycle
(And no one is using it yet). Let's remove it.

Signed-off-by: Kuninori Morimoto <[e-mail]>
Acked-by: Rob Herring (Arm) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

Documentation/devicetree/bindings/sound/renesas,rsnd.yaml

···
     description: List of necessary clock names.
     # details are defined below
 
-  post-init-providers:
-    description: At least if rsnd is using DPCM connection on Audio-Graph-Card2,
-      fw_devlink might doesn't have enough information to break the cycle. rsnd
-      driver will not be probed in such case. Same problem might occur with
-      Multi-CPU/Codec or Codec2Codec.
-
   # ports is below
   port:
     $ref: audio-graph-port.yaml#/definitions/port-base