ramips: fix Sitecom WL-341v3 board and image names

The following patch changes:
 * board name from "wl341v3" to "wl-341v3"
 * dts filename
 * LED names in dts file

for Sitecom WL-341v3 device.

Signed-off-by: Piotr Dymacz <pepe2k@gmail.com>

SVN-Revision: 46622