phy: add the Berlin USB PHY driver

Add the driver driving the Marvell Berlin USB PHY. This allows to
initialize the PHY and to use it from the USB driver later.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

diff --cc drivers/phy/Kconfig
Simple merge

diff --cc drivers/phy/Makefile
Simple merge

diff --cc drivers/phy/phy-berlin-usb.c
Simple merge