ARM: dts: berlin: add BG2CD nodes for USB support

Adds nodes describing the Marvell Berlin BG2CD USB PHY and USB. The BG2CD
SoC has 2 USB ChipIdea controllers, with usb0 host-only and usb1 dual-role
capable.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>