Creates /etc/device_info which will be used to fill in information for
WPS and other protocols that need manufacturer/device information

This helps with creating OpenWrt firmware for OEM or rebranded devices.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@41884 3c298f89-4303-0410-b956-a3cf2f4a3e73