Revert "ACPI: Ignore _BQC object when registering backlight device"

This reverts commit 7c0ea45b which
caused a regression with the backlight being set to off when a laptop
doesn't have a _BQC entry to query the actual backlight value.  The code
blindly then falls back on a value of 0.

See
	http://bugzilla.kernel.org/show_bug.cgi?id=10387
	http://lkml.org/lkml/2008/4/2/366

for details.
Bisected-and-reported-by: Andrey Borzenkov <arvidjaar@mail.ru>
Cc: Zhao Yakui <yakui.zhao@intel.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <len.brown@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/acpi/video.c

@@ -713,7 +713,7 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
 
 	kfree(obj);
 
-	if (device->cap._BCL && device->cap._BCM && max_level > 0) {
+	if (device->cap._BCL && device->cap._BCM && device->cap._BQC && max_level > 0){
 		int result;
 		static int count = 0;
 		char *name;