ARM: EXYNOS4: Add usb ehci device to the SMDKV310

This patch is to support usb ehci device to the SMDKV310 board.

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>