PM / OPP: dev_pm_opp_set_sharing_cpus() doesn't depend on CONFIG_OF

dev_pm_opp_set_sharing_cpus() doesn't do any DT specific stuff and its
declarations are added within the CONFIG_OF ifdef by mistake. Take them
out of that.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>