Macros defined in exynos5_setup.h specific to SMDK5420
are required for Peach-Pit too. Hence, replacing
CONFIG_SMDK5420 with CONFIG_EXYNOS5420 to enable these
macros for all the boards based on Exynos5420.

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