When a full/low speed device is connected to USB 2.0 port on UniPhier SoC
that has ehci controller, the kernel shows the following messages.

| usb usb1-port1: Cannot enable. Maybe the USB cable is bad?
| usb usb1-port1: Cannot enable. Maybe the USB cable is bad?
| usb usb1-port1: Cannot enable. Maybe the USB cable is bad?
| usb usb1-port1: unable to enumerate USB device

To fix the issue, the driver needs to enable Transaction Translator on ehci
root hub. This adds 'has-transaction-translator' property to each node.
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>