arm: kirkwood: add ZyXEL NSA310S device

This patch add ZyXEL NSA310S 1-Bay Media Server

The ZyXEL NSA310S device is a Kirkwood based NAS:

- SoC: Marvell 88F6702 1000Mhz
- SDRAM memory: 256MB DDR2 400Mhz
- Gigabit ethernet: PHY Marvell 88E1318
- Flash memory: 128MB
- 1 Power button
- 1 Power LED (blue)
- 4 Status LED (green)
- 1 Copy/Sync button
- 1 Reset button
- 1 SATA II port
- 2 USB 2.0 ports (front and back)
- Smart fan

Signed-off-by: Gerald Kerma <dreagle@doukki.net>
Signed-off-by: Tony Dinh <mibodhi@gmail.com>
Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>
diff --git a/arch/arm/mach-kirkwood/Kconfig b/arch/arm/mach-kirkwood/Kconfig
index f7737bf..9205b1e 100644
--- a/arch/arm/mach-kirkwood/Kconfig
+++ b/arch/arm/mach-kirkwood/Kconfig
@@ -49,6 +49,9 @@
 config TARGET_NAS220
 	bool "BlackArmor NAS220"
 
+config TARGET_NSA310S
+	bool "Zyxel NSA310S"
+
 endchoice
 
 config SYS_SOC
@@ -69,5 +72,6 @@
 source "board/Seagate/dockstar/Kconfig"
 source "board/Seagate/goflexhome/Kconfig"
 source "board/Seagate/nas220/Kconfig"
+source "board/zyxel/nsa310s/Kconfig"
 
 endif