kirkwood: add support for Netgear Stora (MS2000/2110) NAS

Dual-slot NAS based on Marvell Kirkwood.

Specifications:
 - Marvell 88F6281 @1GHZ
 - 128Mb RAM
 - 256Mb NAND
 - 1x GbE LAN (Marvell 88E1116)
 - 1x USB 2.0
 - 2x SATA
 - PCF8563 RTC
 - LM75 sensor
 - TC654 PWM fan controller
 - Serial on J2 (115200,8n1)
 - Newer bootROM so kwboot-ing via serial is possible

Installation:

1. Serial console
 - Connect your levelshifter to the serial console
   on J2 (refer to the wiki page for pinout)
2. Update u-boot
 - Download the u-boot.kwb image for the device
 - Powercycle the NAS
 - Run "kwboot -b ./u-boot.kwb /dev/ttyUSB0 -p"
 - Connect to the serial console with minicom
 - tftp 0x0800000 netgear_stora-u-boot.kwb
 - nand erase 0x0 100000
 - nand write 0x0800000 0x0 0x100000
 - reset
3. Install OpenWrt
 - Boot up the initramfs image
 - tftpboot 0x800000 openwrt-kirkwood-netgear_stora-initramfs-uImage; bootm 0x800000
 - Download the sysupgrade image and perform sysupgrade

The fan is controlled in 3 stages by a script running every minute
from cron, measuring the CPU temperature.

Snippets taken from bodhi <mibodhi@gmail.com>

Signed-off-by: Zoltan HERPAI <wigyori@uid0.hu>

package/boot/uboot-kirkwood/Makefile

@@ -65,6 +65,11 @@ define U-Boot/nas220
   BUILD_DEVICES:=seagate_blackarmor-nas220
 endef
 
+define U-Boot/netgear_ms2110
+  NAME:=Netgear Stora (MS2000/2110)
+  BUILD_DEVICES:=netgear_stora
+endef
+
 define U-Boot/nsa310
   NAME:=Zyxel NSA310
   BUILD_DEVICES:=zyxel_nsa310b
@@ -107,6 +112,7 @@ UBOOT_TARGETS := \
 	iconnect iconnect_second_stage \
 	l-50 \
 	nas220 \
+	netgear_ms2110 \
 	nsa310 \
 	nsa310s \
 	nsa325 \