pinctrl: mediatek: fix the pinconf register offset of some pins

pinctrl: mediatek: fix the pinconf register offset of some pins

Correct the bias-pull-up, bias-pull-down and bias-disable register
offset of mt7986 pin-42 to pin-49, in the original driver, the
relative offset value was erroneously decremented by 1.

Fixes: 360de6728064 ("pinctrl: mediatek: add support for MT7986 SoC")
Signed-off-by: Sam Shih <sam.shih@mediatek.com>
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20221106080114.7426-5-linux@fw-web.de
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>