ACPI / dock: Use ACPI device object pointers instead of ACPI handles

Rework the ACPI dock station driver to store ACPI device object
pointers instead of ACPI handles in its internal data structures.

The purpose is moslty to make subsequent simplifications possible,
but also this allows the overall code size to be reduced slightly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h
index b124fdb..d6c98b9 100644
--- a/include/acpi/acpi_drivers.h
+++ b/include/acpi/acpi_drivers.h
@@ -116,7 +116,7 @@
 };
 
 #ifdef CONFIG_ACPI_DOCK
-extern int is_dock_device(acpi_handle handle);
+extern int is_dock_device(struct acpi_device *adev);
 extern int register_hotplug_dock_device(acpi_handle handle,
 					const struct acpi_dock_ops *ops,
 					void *context,
@@ -124,7 +124,7 @@
 					void (*release)(void *));
 extern void unregister_hotplug_dock_device(acpi_handle handle);
 #else
-static inline int is_dock_device(acpi_handle handle)
+static inline int is_dock_device(struct acpi_device *adev)
 {
 	return 0;
 }