dt-bindings: pinctrl: mt8192: Add gpio-line-names property

dt-bindings: pinctrl: mt8192: Add gpio-line-names property

Add the gpio-line-names optional property to the pinctrl-mt8192 binding
to prevent dt_binding_check warnings when it is present in the pinctrl
node in the Devicetree.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220315211936.442708-5-nfraprado@collabora.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>