ramips: add support for Sitecom WL-341v3 and other Sercomm IP1006RRv2 boards

ramips: add support for Sitecom WL-341v3 and other Sercomm IP1006RRv2 boards

This patch adds support for the Sitecom WL-341 v3 and other Sercomm
IP1006RRv2 based boards for sysupgrade support and for the initial
flash through pushbutton initiated recovery mode with the special
partition table and fixes for the quirks and things required by the
modified bootloader.

There is a known bug, Wi-Fi is not working on my board probably
because of the lack of RAM (the board only has 16MiB ram -- half of
the normal amount for non rebadged versions, but there is an empty
slot for another ram chip,) but I don't know for sure. The driver
loads but hostapd fails to load so I think it's not related to the
specific device except for the lack of RAM.

Moreover, only 7 of the 11 onboard leds are confirmed working, it
seems that one of the others is always on and the remaining ones are
connected to the wireless card leds already recognized by OpenWrt

[juhosg: reordered some parts in order to keep things sorted
alphabetically]

Signed-off-by: Marco Antonio Mauro <marcus90@gmail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@29910 3c298f89-4303-0410-b956-a3cf2f4a3e73