ARM: shmobile: pm-rmobile: Postpone call to pm_genpd_init()

All local setup of the generic_pm_domain structure should have been
completed before calling pm_genpd_init().

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>