The Kconfig option belongs closer to the corresponding implementation,
hence let's move it from the soc subsystem to the pmdomain subsystem.

Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: <linux-samsung-soc@vger.kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>