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>
diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
index f32bd47..ff30582 100644
--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -310,8 +310,6 @@
 static struct acpi_device * dock_create_acpi_device(acpi_handle handle)
 {
 	struct acpi_device *device;
-	struct acpi_device *parent_device;
-	acpi_handle parent;
 	int ret;
 
 	if (acpi_bus_get_device(handle, &device)) {
@@ -319,16 +317,9 @@
 		 * no device created for this object,
 		 * so we should create one.
 		 */
-		acpi_get_parent(handle, &parent);
-		if (acpi_bus_get_device(parent, &parent_device))
-			parent_device = NULL;
-
-		ret = acpi_bus_add(&device, parent_device, handle,
-			ACPI_BUS_TYPE_DEVICE);
-		if (ret) {
+		ret = acpi_bus_add(handle, &device);
+		if (ret)
 			pr_debug("error adding bus, %x\n", -ret);
-			return NULL;
-		}
 	}
 	return device;
 }