ARM: exynos: cleanup kconfig option display

The addition of Exynos to multi-platform configs creates a mess of config
options with options appearing before the Exynos config option. This is
due to arch/arm/plat-samsung/Kconfig being included out of order with the
other Samsung platform kconfig files. Reorder the kconfig files and move
all the options into a sub-menu. Some of the options are dead, so remove
those as well.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: linux-samsung-soc@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>