dt-bindings: gpio: vf610: Allow gpio-line-names to be set

Describe common "gpio-line-names" property to allow DTs to
specify names for GPIO lines.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240708084107.38986-2-frieder@fris.de


Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>