dt-bindings: timer: Add compatibles for sun50i timers

The sun50i SoCs contain timer blocks which are useful as broadcast
clockevent sources. They each have 2 interrupts, matching the A23
variant, so add the new compatible strings with the A23 compatible
as a fallback.

Acked-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210322044707.19479-3-samuel@sholland.org