This patch intends to add DDR3 initialization code for Exynos5420.

Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Signed-off-by: Rajeshwari S Shinde <rajeshwari.s@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>