ARM: mvebu: add Device Tree description for the EHCI controllers on Armada 375

The Marvell Armada 375 SoCs contains two EHCI controllers. This commit
adds the Device Tree description of these interfaces at the SoC level,
and also enables the USB2 port on the Armada 375 DB platform.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Link: https://lkml.kernel.org/r/1400149062-32661-18-git-send-email-gregory.clement@free-electrons.com


Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>