ARM: dts: NSP: Add EHCI/OHCI USB nodes to device tree

Add the EHCI and OHCI entries to the Northstar Plus device tree files.

Signed-off-by: Yendapally Reddy Dhananjaya Reddy <yendapally.reddy@broadcom.com>
Signed-off-by: Jon Mason <jon.mason@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>