ARM: dts: Exynos5420: add CPU OPP and regulator supply property

ARM: dts: Exynos5420: add CPU OPP and regulator supply property

For Exynos5420 platforms, add CPU operating points and CPU
regulator supply properties for migrating from Exynos specific
cpufreq driver to using generic cpufreq driver.

Changes by Bartlomiej:
- split Exynos5420 support from the original patch

Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Doug Anderson <dianders@chromium.org>
Cc: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Cc: Andreas Faerber <afaerber@suse.de>
Cc: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>