Because PLAT_SAMSUNG isn't include exynos SoCs for arm64, but
ARCH_EXYNOS can do it. And it also needs to add ARCH_S3C64XX instead of
PLAT_SAMSUNG.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>