ARM: shmobile: Move sh7372's PM domain objects to a table

Instead of giving a name to every sh7372's PM domain object, put them
all into a table and use rmobile_init_domains(), introduced by a
previous patch, for initializing them all altogether.  Also, use
pm_genpd_add_subdomain_names() for adding subdomains to the PM
domains and pm_genpd_poweron_name() for turning on the A4S domain
when preparing for system suspend.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@opensource.se>