ipq806x: enable and setup multi-CPU port for qca8k switch

ipq806x: enable and setup multi-CPU port for qca8k switch

Enable and setup multi-cpu for qca8k switch for ipq806x based devices.

Rework each DTS to enable the secondary CPU port on QCA8K switch and
apply the required values originally set by the OEM in the old swconfig
node.

In original firmware the first CPU port was always assigned to the WAN
port and the secondary CPU port was assigned to the rest of the LAN
port. Follow this original implementation using an init.d script.

To setup the CPU port ip tools is required. Add additional default
package ip-tiny to correctly setup the CPU port.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>