PM / Domains: Fix unsafe iteration over modified list of domain providers

of_genpd_del_provider() iterates over list of domain provides and
removes matching element thus it has to use safe version of list
iteration.

Fixes: aa42240ab254 (PM / Domains: Add generic OF-based PM domain look-up)
Cc: 3.19+ <stable@vger.kernel.org> # 3.19+
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/domain.c

@@ -1835,12 +1835,12 @@ EXPORT_SYMBOL_GPL(of_genpd_add_provider_onecell);
  */
 void of_genpd_del_provider(struct device_node *np)
 {
-	struct of_genpd_provider *cp;
+	struct of_genpd_provider *cp, *tmp;
 	struct generic_pm_domain *gpd;
 
 	mutex_lock(&gpd_list_lock);
 	mutex_lock(&of_genpd_mutex);
-	list_for_each_entry(cp, &of_genpd_providers, link) {
+	list_for_each_entry_safe(cp, tmp, &of_genpd_providers, link) {
 		if (cp->node == np) {
 			/*
 			 * For each PM domain associated with the