pinctrl: meson-gxbb: Add missing GPIODV_18 pin entry

GPIODV_18 entry was missing in the original driver push.

Fixes: 468c234f ("pinctrl: amlogic: Add support for Amlogic Meson GXBB SoC")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>