dt-bindings: gpio: Add AXP221/AXP223/AXP809 compatibles

These PMICs each have 2 GPIOs with the same register layout as AXP813,
but without an ADC function.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220621034224.38995-2-samuel@sholland.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>