PM / OPP: Relocate few routines

In order to prepare for the later commits, this relocates few routines
towards the top as they will be used earlier in the code.

Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit 737002b5de3d15b3012feea17f782a628b24699b)
Signed-off-by: Alex Shi <alex.shi@linaro.org>