dt-bindings: iio: adc: Document Renesas RZ/V2L ADC

Document renesas RZ/V2L ADC bindings. RZ/V2L ADC is identical to RZ/G2L
with same number of channels.

While at it remove RZ/G2LC SoC from binding documentation as it does not
support ADC.

Signed-off-by: Biju Das <[e-mail]>
Acked-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

Documentation/devicetree/bindings/iio/adc/renesas,rzg2l-adc.yaml

···
   compatible:
     items:
       - enum:
-          - renesas,r9a07g044-adc   # RZ/G2{L,LC}
+          - renesas,r9a07g044-adc   # RZ/G2L
+          - renesas,r9a07g054-adc   # RZ/V2L
       - const: renesas,rzg2l-adc
 
   reg: