ARM: dts: NSP: Add BCM958625HR switch ports

Add the layout of the switch ports found on the BCM958625HR reference
board. The CPU port is hooked up to the AMAC0 Ethernet controlelr
adapter, so we also enable it.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>