ACPI: video: fix acpi_backlight=video

Make "acpi_backlight=video" param enable ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO
as intended, instead of incorrectly enabling video output switching.

BugLink: http://bugs.launchpad.net/bugs/573120

Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: <stable@kernel.org>
Acked-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/video_detect.c

@@ -250,7 +250,7 @@ static int __init acpi_backlight(char *str)
 				ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
 		if (!strcmp("video", str))
 			acpi_video_support |=
-				ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
+				ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO;
 	}
 	return 1;
 }