arm64: dts: exynos: Add USB 3.0 controller node for Exynos7

Add USB 3.0 DRD controller device node, with its clock
and phy information to enable the same on Exynos7.

Signed-off-by: Vivek Gautam <gautamvivek1987@gmail.com>
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>