soc: actions: Move power-domain driver to the genpd dir

To simplify with maintenance let's move the action power-domain driver to
the new genpd directory. Going forward, patches are intended to be managed
through a separate git tree, according to MAINTAINERS.

Cc: "Andreas Färber" <[e-mail]>
Cc: Manivannan Sadhasivam <[e-mail]>
Cc: <[e-mail]>
Acked-by: Manivannan Sadhasivam <[e-mail]>
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/genpd/Makefile

···
 # SPDX-License-Identifier: GPL-2.0-only
+obj-y					+= actions/

drivers/genpd/actions/Makefile

···
+# SPDX-License-Identifier: GPL-2.0+
+obj-$(CONFIG_OWL_PM_DOMAINS)		+= owl-sps.o

drivers/soc/actions/Makefile

···
 # SPDX-License-Identifier: GPL-2.0+
 
 obj-$(CONFIG_OWL_PM_DOMAINS_HELPER) += owl-sps-helper.o
-obj-$(CONFIG_OWL_PM_DOMAINS) += owl-sps.o