mips: Add Gardena Smart-Gateway board support

The Gardena Smart-Gateway boards have a MT7688 SoC with 128 MiB of RAM
and 8 MiB of flash (SPI NOR) and additional 128MiB SPI NAND storage.

This patch also includes 2 targets. One is the target that can be
programmed into the SPI NOR flash and a 2nd target "xxx-ram" is
added to support loading and booting via an already running U-Boot
version. This allows easy development and testing without the
need to flash the image each time.

Signed-off-by: Stefan Roese <sr@denx.de>
[fixed and regenerated defconfig files]
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
diff --git a/board/gardena/smart-gateway-mt7688/Kconfig b/board/gardena/smart-gateway-mt7688/Kconfig
new file mode 100644
index 0000000..3653f8a
--- /dev/null
+++ b/board/gardena/smart-gateway-mt7688/Kconfig
@@ -0,0 +1,12 @@
+if BOARD_GARDENA_SMART_GATEWAY_MT7688
+
+config SYS_BOARD
+	default "smart-gateway-mt7688"
+
+config SYS_VENDOR
+	default "gardena"
+
+config SYS_CONFIG_NAME
+	default "gardena-smart-gateway-mt7688"
+
+endif
diff --git a/board/gardena/smart-gateway-mt7688/MAINTAINERS b/board/gardena/smart-gateway-mt7688/MAINTAINERS
new file mode 100644
index 0000000..bbb491c
--- /dev/null
+++ b/board/gardena/smart-gateway-mt7688/MAINTAINERS
@@ -0,0 +1,8 @@
+GARDENA_SMART_GATEWAY_MT7688 BOARD
+M:	Stefan Roese <sr@denx.de>
+S:	Maintained
+F:	board/gardena/smart-gateway-mt7688
+F:	include/configs/gardena-smart-gateway-mt7688.h
+F:	configs/gardena-smart-gateway-mt7688_defconfig
+F:	configs/gardena-smart-gateway-mt7688-ram_defconfig
+F:	arch/mips/dts/gardena-smart-gateway-mt7688.dts
diff --git a/board/gardena/smart-gateway-mt7688/Makefile b/board/gardena/smart-gateway-mt7688/Makefile
new file mode 100644
index 0000000..70cd7a8
--- /dev/null
+++ b/board/gardena/smart-gateway-mt7688/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0+
+
+obj-y += board.o
diff --git a/board/gardena/smart-gateway-mt7688/board.c b/board/gardena/smart-gateway-mt7688/board.c
new file mode 100644
index 0000000..5ff546f
--- /dev/null
+++ b/board/gardena/smart-gateway-mt7688/board.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Stefan Roese <sr@denx.de>
+ */
+
+#include <common.h>
+#include <asm/io.h>
+
+int board_early_init_f(void)
+{
+	/*
+	 * Nothing to be done here for this board (no UART setup etc)
+	 * right now. We might need some pin muxing, so lets keep this
+	 * function for now.
+	 */
+	return 0;
+}