pinctrl: pinconf-generic: Add support for "output-impedance-ohms" to be extracted from DT files

Add "output-impedance-ohms" property to generic options used for DT
parsing files. This enables drivers, which use generic pin configurations,
to get the value passed to this property.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20211027134509.5036-3-prabhakar.mahadev-lad.rj@bp.renesas.com


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