dt-bindings: leds: Add gpio-line-names to PCA9532 GPIO

This is a gpio-controller, so gpio-line-names should be allowed as well.

pca9532 supports up to 16 GPIOs.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230724063520.182888-2-alexander.stein@ew.tq-group.com


Signed-off-by: Lee Jones <lee@kernel.org>