ARM: exynos5440: create a DT header defining CLK IDs

The patch adds header file defining clock IDs.
This allows to use macros instead of magic numbers in DT bindings.

Signed-off-by: Andrzej Hajda <a.hajda-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Signed-off-by: Kyungmin Park <kyungmin.park-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Acked-by: Mike Turquette <mturquette@linaro.org>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Tomasz Figa <t.figa@samsung.com>