dell-wmi: Port to new backlight interface selection API

Port the backlight selection logic to the new backlight interface
selection API.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Pali Rohár <pali.rohar@gmail.com>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/platform/x86/dell-wmi.c

@@ -35,6 +35,7 @@
 #include <linux/acpi.h>
 #include <linux/string.h>
 #include <linux/dmi.h>
+#include <acpi/video.h>
 
 MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
 MODULE_DESCRIPTION("Dell laptop WMI hotkeys driver");
@@ -397,7 +398,7 @@ static int __init dell_wmi_init(void)
 	}
 
 	dmi_walk(find_hk_type, NULL);
-	acpi_video = acpi_video_backlight_support();
+	acpi_video = acpi_video_get_backlight_type() != acpi_backlight_vendor;
 
 	err = dell_wmi_input_setup();
 	if (err)