usb: phy: samsung: Add PHY support for USB 3.0 controller

Adding PHY driver support for USB 3.0 controller for Samsung's
SoCs.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>