ARM: dts: add ohci and ehci controller nodes for EXYNOS5440

EXYNOS5440 includes both OHCI and EHCI usb host controllers.
This patch adds device tree nodes for both of them. And the
EHCI and OHCI controllers on exynos5440 do not need any
explicit phy configuration. So need to assign a different
compatible value for these controllers.

Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>