ARM: s3c: mark as deprecated and schedule removal

The Samsung S3C24xx and S3C64xx platforms are very old designs. S3C2416
was introduced in 2008 and S3C6410 in 2009/2010.  They are not widely
available anymore - out-of-stock on FriendlyArm (one of manufacturers of
boards) and only few specialist stores still offer them for quite a high
price.

The community around these platforms was not very active, so I suspect
no one really uses them anymore. Maintenance takes precious time so
there is little sense in keeping them alive if there are no real users.

Let's mark all S3C24xx and S3C64xx platforms as deprecated and mention
possible removal in after 2022 for the first and 2024 for the lattere.
The deprecation message will be as text in Kconfig, build message (not a
warning though) and runtime print error.

If there are any users, they might respond and postpone the removal.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Tomasz Figa <tomasz.figa@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20220407072319.75614-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Arnd Bergmann <arnd@arndb.de>