PM / OPP: Staticize __dev_pm_opp_remove()

Its a local routine and need not be accessible outside of opp.c.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/opp.c

@@ -518,7 +518,8 @@ static void kfree_device_rcu(struct rcu_head *head)
 	kfree_rcu(device_opp, rcu_head);
 }
 
-void __dev_pm_opp_remove(struct device_opp *dev_opp, struct dev_pm_opp *opp)
+static void __dev_pm_opp_remove(struct device_opp *dev_opp,
+				struct dev_pm_opp *opp)
 {
 	/*
 	 * Notify the changes in the availability of the operable