ARM: at91/dt: sam9n12ek: ohci: add port and vbus property

Add the port number and vbus property for ohci port, or else if
bootloader won't configure the vbus pin, the 5v supply is not
power on, so can not work with usb devices.

Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>