pinctrl: meson: fix bit manipulation of pin bias configuration

This fixes the wrong usage of clrsetbits_le32(), badly setting the set argument.

Fixes: c4c726c2 ("pinctrl: meson: add pinconf support")
Reported-by: Anton Arapov <arapov@gmail.com>
Reported-by: Otto Meier <gf435@gmx.net>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>