intel-oaktrail: Port to new backlight interface selection API

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

This commit also removes various obsolete pr_xxx messages related to
backlight interface selection. These are obsolete because they assume
there is only a vendor or acpi backlight driver and no other choice.
Also they are not necessary, if the user wants to know which backlight
interfaces are registered a simple "ls /sys/class/backlight" suffices.

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

drivers/platform/x86/intel_oaktrail.c

@@ -50,6 +50,7 @@
 #include <linux/platform_device.h>
 #include <linux/dmi.h>
 #include <linux/rfkill.h>
+#include <acpi/video.h>
 
 #define DRIVER_NAME	"intel_oaktrail"
 #define DRIVER_VERSION	"0.4ac1"
@@ -343,13 +344,11 @@ static int __init oaktrail_init(void)
 		goto err_device_add;
 	}
 
-	if (!acpi_video_backlight_support()) {
+	if (acpi_video_get_backlight_type() == acpi_backlight_vendor) {
 		ret = oaktrail_backlight_init();
 		if (ret)
 			goto err_backlight;
-
-	} else
-		pr_info("Backlight controlled by ACPI video driver\n");
+	}
 
 	ret = oaktrail_rfkill_init();
 	if (ret) {