ARM: s5pv210: don't imply CONFIG_PLAT_SAMSUNG

The plat-samsung directory and mach-s5pv210 can be build
completely independently, so split the two Kconfig symbols
CONFIG_PLAT_SAMSUNG and CONFIG_ARCH_S5PV210.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20200806182059.2431-18-krzk@kernel.org


Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>