dt-bindings: pinctrl: renesas,rzg2l-pinctrl: Allow schmitt and open drain properties

On the RZ/V2H(P) SoC one can configure the 'input-schmitt-{enable,disable}',
'drive-open-drain' and 'drive-push-pull' of multiplexed pins. Update the
binding documentation to include these properties.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/20241004123658.764557-2-prabhakar.mahadev-lad.rj@bp.renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>