PM / Domains: Remove reference counting for the generic_pm_domain_data

The reference counting was needed when genpd supported PM domain device
callbacks. Since this option has been removed, let's also remove the
reference counting of the struct generic_pm_domain_data.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --cc drivers/base/power/domain.c
Simple merge

diff --cc include/linux/pm_domain.h
Simple merge