arm64: dts: Add Broadcom Northstar2 device tree entries for PDC driver.

Add Broadcom Northstar2 SoC device tree entries for PDC driver.

Signed-off-by: Rob Rice <rob.rice@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>