ARM: s3c64xx: Leave disabling of unused PM domains to genpd

Since genpd at late init, will try to disable unused PM domains we
don't need to do it from the machine specific code as well.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>