ACPI: EC: acpi_ec_remove(): fix use-after-free

This patch fixes an obvious use-after-free introduced by
commit 837012ed.

Spotted by the Coverity checker.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/ec.c

@@ -730,14 +730,14 @@ static int acpi_ec_add(struct acpi_device *device)
 static int acpi_ec_remove(struct acpi_device *device, int type)
 {
 	struct acpi_ec *ec;
-	struct acpi_ec_query_handler *handler;
+	struct acpi_ec_query_handler *handler, *tmp;
 
 	if (!device)
 		return -EINVAL;
 
 	ec = acpi_driver_data(device);
 	mutex_lock(&ec->lock);
-	list_for_each_entry(handler, &ec->list, node) {
+	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
 		list_del(&handler->node);
 		kfree(handler);
 	}