ACPI: video: Add backlight=native DMI quirk for Lenovo Ideapad Z470

The Lenovo Ideapad Z470 predates Windows 8, so it defaults to using
acpi_video for backlight control. But this is not functional on this
model.

Add a DMI quirk to use the native backlight interface which works.

Link: https://bugzilla.suse.com/show_bug.cgi?id=1208724Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/video_detect.c

@@ -445,6 +445,15 @@ static const struct dmi_system_id video_detect_dmi_table[] = {
 		DMI_MATCH(DMI_BOARD_NAME, "Lenovo IdeaPad S405"),
 		},
 	},
+	{
+	 /* https://bugzilla.suse.com/show_bug.cgi?id=1208724 */
+	 .callback = video_detect_force_native,
+	 /* Lenovo Ideapad Z470 */
+	 .matches = {
+		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+		DMI_MATCH(DMI_PRODUCT_VERSION, "IdeaPad Z470"),
+		},
+	},
 	{
 	 /* https://bugzilla.redhat.com/show_bug.cgi?id=1187004 */
 	 .callback = video_detect_force_native,