ARM: dts: Add usb2phy to exynos5250

Add support to PHY of USB2 of the Exynos5250 SoC.

Signed-off-by: Kamil Debski <k.debski@samsung.com>
[gautam.vivek@samsung.com: Split the usb phy entries]
[gautam.vivek@samsung.com: Added phy entry for OHCI also along with EHCI]
Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Signed-off-by: Vikas Sajjan <vikas.sajjan@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>