boards: arm: gd32a503v_eval: enable CONFIG_GPIO in board kconfig

GPIO/UART are considered "minimal peripherals" by samples,
should enable by default.

Signed-off-by: YuLong Yao <[email protected]>

Author: feilongfl

boards/arm/gd32a503v_eval/gd32a503v_eval_defconfig

@@ -11,3 +11,5 @@ CONFIG_HW_STACK_PROTECTION=y
 CONFIG_CONSOLE=y
 CONFIG_UART_CONSOLE=y
 CONFIG_SERIAL=y
+
+CONFIG_GPIO=y