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/board/zyxel/nsa310s/kwbimage.cfg b/board/zyxel/nsa310s/kwbimage.cfg
new file mode 100644
index 0000000..e8f4b8a
--- /dev/null
+++ b/board/zyxel/nsa310s/kwbimage.cfg
@@ -0,0 +1,43 @@
+#
+# Copyright (C) 2015
+# Gerald Kerma <dreagle@doukki.net>
+# Tony Dinh <mibodhi@gmail.com>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+# Refer to doc/README.kwbimage for more details about how-to
+# configure and create kirkwood boot images.
+#
+
+# Boot Media configurations
+BOOT_FROM       nand
+NAND_ECC_MODE   default
+NAND_PAGE_SIZE  0x0800
+
+# Configure RGMII-0 interface pad voltage to 1.8V
+DATA 0xFFD100e0 0x1b1b1b9b
+
+DATA 0xFFD01400 0x43010c30
+DATA 0xFFD01404 0x39543000
+DATA 0xFFD01408 0x22125451
+DATA 0xFFD0140C 0x00000833
+DATA 0xFFD01410 0x0000000C
+DATA 0xFFD01414 0x00000000
+DATA 0xFFD01418 0x00000000
+DATA 0xFFD0141C 0x00000652
+DATA 0xFFD01420 0x00000004
+DATA 0xFFD01424 0x0000F17F
+DATA 0xFFD01428 0x00085520
+DATA 0xFFD0147c 0x00008552
+DATA 0xFFD01504 0x0FFFFFF1
+DATA 0xFFD01508 0x10000000
+DATA 0xFFD0150C 0x00000000
+DATA 0xFFD01514 0x00000000
+DATA 0xFFD0151C 0x00000000
+DATA 0xFFD01494 0x00010000
+DATA 0xFFD01498 0x00000000
+DATA 0xFFD0149C 0x0000E403
+DATA 0xFFD01480 0x00000001
+DATA 0xFFD20134 0x66666666
+DATA 0xFFD20138 0x66666666
+DATA 0x0 0x0