exynos5: dts: Add COMPAT string data for USB 3.0 PHY and XHCI

Adding required compatible string for xHCI host controller
as well as USB 3.0 PHY to enable dt support for usb 3.0 on
exynos5.

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Cc: Julius Werner <jwerner@chromium.org>
Cc: Simon Glass <sjg@chromium.org>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Marek Vasut <marex@denx.de>