dt-bindings: spi: sunxi: Add H616 compatible string

Add the obvious compatible name to the existing SPI binding, and pair
it with the existing H3 fallback compatible string, as the devices are
compatible.
Signed-off-by: NAndre Przywara <andre.przywara@arm.com>
Acked-by: NRob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210125151811.11871-14-andre.przywara@arm.comSigned-off-by: NMark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/allwinner,sun6i-a31-spi.yaml

@@ -25,6 +25,7 @@ properties:
           - enum:
               - allwinner,sun8i-r40-spi
               - allwinner,sun50i-h6-spi
+              - allwinner,sun50i-h616-spi
           - const: allwinner,sun8i-h3-spi
 
   reg: