PM: domains: Consolidate genpd_restore_noirq() and genpd_resume_noirq()

Most of the logic between genpd_restore_noirq() and genpd_resume_noirq()
are identical.  The suspended_count decrement for restore should be the
right thing to do anyway, considering there is an increment in
genpd_finish_suspend() for hibernation.  So consolidate these two
functions into genpd_finish_resume().

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>