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/arch/mips/mach-mt7620/Kconfig b/arch/mips/mach-mt7620/Kconfig
index ef1211d..13a7bd2 100644
--- a/arch/mips/mach-mt7620/Kconfig
+++ b/arch/mips/mach-mt7620/Kconfig
@@ -21,6 +21,14 @@
 choice
 	prompt "Board select"
 
+config BOARD_GARDENA_SMART_GATEWAY_MT7688
+	bool "Gardena Smart Gateway"
+	depends on SOC_MT7620
+	select SUPPORTS_BOOT_RAM
+	help
+	  Gardena Smart Gateway boards have a MT7688 SoC with 128 MiB of RAM
+	  and 8 MiB of flash (SPI NOR) and additional SPI NAND storage.
+
 config BOARD_LINKIT_SMART_7688
 	bool "LinkIt Smart 7688"
 	depends on SOC_MT7620
@@ -121,6 +129,7 @@
 config SUPPORTS_BOOT_RAM
 	bool
 
+source "board/gardena/smart-gateway-mt7688/Kconfig"
 source "board/seeed/linkit-smart-7688/Kconfig"
 
 endmenu