ASoC: dt-bindings: tas2770: add compatible for TAS5770L

A variant of TAS2770 known as TAS5770L is found in Apple Silicon Macs.

Reviewed-by: Neal Gompa <[e-mail]>
Acked-by: Rob Herring (Arm) <[e-mail]>
Signed-off-by: James Calligeros <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

Documentation/devicetree/bindings/sound/ti,tas2770.yaml

···
   compatible:
     enum:
       - ti,tas2770
+      - ti,tas5770l # Apple variant
 
   reg:
     maxItems: 1