arm64: dts: NS2: enable PAXC on NS2 SVK

This enables the PAXC based PCIe root complex on NS2 SVK. The PAXC based
root complex is connected to internally emulated PCIe endpoints

Signed-off-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Jon Mason <jon.mason@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>