asus-laptop: 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/asus-laptop.c

@@ -54,6 +54,7 @@
 #include <linux/slab.h>
 #include <linux/dmi.h>
 #include <linux/acpi.h>
+#include <acpi/video.h>
 
 #define ASUS_LAPTOP_VERSION	"0.42"
 
@@ -1884,12 +1885,11 @@ static int asus_acpi_add(struct acpi_device *device)
 	if (result)
 		goto fail_platform;
 
-	if (!acpi_video_backlight_support()) {
+	if (acpi_video_get_backlight_type() == acpi_backlight_vendor) {
 		result = asus_backlight_init(asus);
 		if (result)
 			goto fail_backlight;
-	} else
-		pr_info("Backlight controlled by ACPI video driver\n");
+	}
 
 	result = asus_input_init(asus);
 	if (result)