ARM: dts: add suspend opp to exynos4412

Mark 800MHz OPP as a suspend opp for Exynos4412 based
boards so effectively cpufreq-dt driver behavior w.r.t.
suspend frequency matches what the old exynos-cpufreq
driver has been doing.

This patch fixes suspend/resume support on Exynos4412 based
Trats2 board and reboot hang on Exynos4412 based Odroid U3
board.

Cc: Thomas Abraham <thomas.ab@samsung.com>
Cc: Javier Martinez Canillas <javier@osg.samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>