ACPI: Remove the arguments of acpi_bus_add() that are not used

Notice that acpi_bus_add() uses only 2 of its 4 arguments and
redefine its header to match the body.  Update all of its callers as
necessary and observe that this leads to quite a number of removed
lines of code (Linus will like that).

Add a kerneldoc comment documenting acpi_bus_add() and wonder how
its callers make wrong assumptions about the second argument (make
note to self to take care of that later).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>

drivers/acpi/acpi_memhotplug.c

@@ -157,34 +157,17 @@ static int
 acpi_memory_get_device(acpi_handle handle,
 		       struct acpi_memory_device **mem_device)
 {
-	acpi_status status;
-	acpi_handle phandle;
 	struct acpi_device *device = NULL;
-	struct acpi_device *pdevice = NULL;
 	int result;
 
-
 	if (!acpi_bus_get_device(handle, &device) && device)
 		goto end;
 
-	status = acpi_get_parent(handle, &phandle);
-	if (ACPI_FAILURE(status)) {
-		ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent"));
-		return -EINVAL;
-	}
-
-	/* Get the parent device */
-	result = acpi_bus_get_device(phandle, &pdevice);
-	if (result) {
-		acpi_handle_warn(phandle, "Cannot get acpi bus device\n");
-		return -EINVAL;
-	}
-
 	/*
 	 * Now add the notified device.  This creates the acpi_device
 	 * and invokes .add function
 	 */
-	result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE);
+	result = acpi_bus_add(handle, &device);
 	if (result) {
 		acpi_handle_warn(handle, "Cannot add acpi bus\n");
 		return -EINVAL;