armv8: gpio: add gpio feature

add one struct mpc8xxx_gpio_plat to enable gpio feature.
Signed-off-by: Nhui.song <hui.song_1@nxp.com>
Reviewed-by: NPriyanka Jain <priyanka.jain@nxp.com>

arch/arm/include/asm/arch-fsl-layerscape/gpio.h

+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2020 NXP
+ */
+
+/*
+ * Dummy header file to enable CONFIG_OF_CONTROL.
+ * If CONFIG_OF_CONTROL is enabled, lib/fdtdec.c is compiled.
+ * It includes <asm/arch/gpio.h> via <asm/gpio.h>, so those SoCs that enable
+ * OF_CONTROL must have arch/gpio.h.
+ */
+
+#ifndef __ASM_ARCH_MX85XX_GPIO_H
+#define __ASM_ARCH_MX85XX_GPIO_H
+
+struct mpc8xxx_gpio_plat {
+	ulong addr;
+	ulong size;
+	uint ngpios;
+};
+
+#endif