ramips: add basics for Poray devices

This commit adds the basic elements to support Poray brand routers.
It contains a tool to do the encryption/obfuscation that is used in
Poray routers.

Support for Poray devices was worked on by:

Felix Kaechele <heffer@fedoraproject.org>
Luis Soltero <lsoltero@globalmarinenet.com>
Michel Stempin <michel.stempin@wanadoo.fr>

Signed-off-by: Felix Kaechele <heffer@fedoraproject.org>
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@37635 3c298f89-4303-0410-b956-a3cf2f4a3e73