CONFIG: EXYNOS5: USB: Enable USB 2.0 on smdk5250

Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Acked-by: Minkyu Kang <mk7.kang@samsung.com>