pinctrl: meson-axg: add missing GPIOA_18 gpio group

Without this, the gpio cannot be explicitly mux'ed to its gpio function.

Fixes: 83c5668 ("pinctrl: meson-axg: Add new pinctrl driver for Meson AXG SoC")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Hundebøll <martin@geanix.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Link: https://lore.kernel.org/r/20230512064925.133516-1-martin@geanix.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Author: hundeboll

drivers/pinctrl/meson/pinctrl-meson-axg.c

@@ -400,6 +400,7 @@ static struct meson_pmx_group meson_axg_periphs_groups[] = {
 	GPIO_GROUP(GPIOA_15),
 	GPIO_GROUP(GPIOA_16),
 	GPIO_GROUP(GPIOA_17),
+	GPIO_GROUP(GPIOA_18),
 	GPIO_GROUP(GPIOA_19),
 	GPIO_GROUP(GPIOA_20),