dt-bindings: pinctrl: mt8192: Add RSEL values to bias-pull-{up,down}

Commit fe44e498

 ("pinctrl: mediatek: add rsel setting on mt8192")
added RSEL bias type definition for some pins on mt8192. In order to be
able to configure the bias on those pins, add the RSEL values in the
bias-pull-up and bias-pull-down properties in the binding.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://lore.kernel.org/r/20220627173209.604400-1-nfraprado@collabora.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>