ARM: EXYNOS: Add exynos3250 suspend-to-ram support

This patch supports suspend-to-ram for Exynos3250 SoC
and the SoC doesn't contain L2 cache.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>