pinctrl: exynos: add exynos5420 SoC specific data

Add Samsung EXYNOS5420 SoC specific data to enable pinctrl
support for all platforms based on EXYNOS5420.

Signed-off-by: Leela Krishna Amudala <l.krishna@samsung.com>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Acked-by: Tomasz Figa <t.figa@samsung.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by : Sunil Joshi <joshi@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>