dt-bindings: dma: allwinner,sun50i-a64-dma: Add compatibles for A523

There are two DMA controllers on the A523, one in the main system area
and the other for the MCU. These are the same as the one found on the
A100. The only difference is the DMA endpoint (DRQ) layout.

Since the number of channels and endpoints are described with additional
generic properties, just add new A523-specific compatible strings and
fallback to the A100 one.

Acked-by: Conor Dooley <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Chen-Yu Tsai <[e-mail]>

Documentation/devicetree/bindings/dma/allwinner,sun50i-a64-dma.yaml

···
           - const: allwinner,sun8i-r40-dma
           - const: allwinner,sun50i-a64-dma
       - items:
-          - const: allwinner,sun50i-h616-dma
+          - enum:
+              - allwinner,sun50i-h616-dma
+              - allwinner,sun55i-a523-dma
+              - allwinner,sun55i-a523-mcu-dma
           - const: allwinner,sun50i-a100-dma
 
   reg: