exynos: config: Move common options to the common headers and tidy up

exynos: config: Move common options to the common headers and tidy up

Many options are duplicated on the exynos5 boards. Move these to the common
files. Also some options are not used so can be removed.

Tidy this up to make the files easier to maintain.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Przemyslaw Marczak <p.marczak@samsung.com>