ACPI: bus: Introduce acpi_dev_for_each_child()

Introduce a wrapper around device_for_each_child() to iterate over
the children of a given ACPI device object.

This function will be used in subsequent change sets.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/acpi/bus.c

@@ -1070,6 +1070,12 @@ int acpi_bus_for_each_dev(int (*fn)(struct device *, void *), void *data)
 }
 EXPORT_SYMBOL_GPL(acpi_bus_for_each_dev);
 
+int acpi_dev_for_each_child(struct acpi_device *adev,
+			    int (*fn)(struct device *, void *), void *data)
+{
+	return device_for_each_child(&adev->dev, data, fn);
+}
+
 /* --------------------------------------------------------------------------
                              Initialization/Cleanup
    -------------------------------------------------------------------------- */

include/acpi/acpi_bus.h

@@ -481,6 +481,8 @@ void acpi_initialize_hp_context(struct acpi_device *adev,
 extern struct bus_type acpi_bus_type;
 
 int acpi_bus_for_each_dev(int (*fn)(struct device *, void *), void *data);
+int acpi_dev_for_each_child(struct acpi_device *adev,
+			    int (*fn)(struct device *, void *), void *data);
 
 /*
  * Events