pinctrl: meson: g12a: add DS bank value

add drive-strength bank regiter and bit value for G12A SoC

Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>