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

Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: <linux-actions@lists.infradead.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>