dt-bindings: irq: sun6i-r: Add a compatible for the H3

The Allwinner H3 SoC contains an R_INTC that is, as far as we know,
compatible with the R_INTC present in other sun8i SoCs starting with
the A31. Since the R_INTC hardware is undocumented, introduce a new
compatible for the R_INTC variant in this SoC, in case there turns out
to be some difference.

Acked-by: Maxime Ripard <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Samuel Holland <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

Documentation/devicetree/bindings/interrupt-controller/allwinner,sun6i-a31-r-intc.yaml

···
       - items:
           - enum:
               - allwinner,sun8i-a83t-r-intc
+              - allwinner,sun8i-h3-r-intc
               - allwinner,sun50i-a64-r-intc
           - const: allwinner,sun6i-a31-r-intc
       - const: allwinner,sun50i-h6-r-intc