backports: drop display output class support

backports: drop display output class support

Jean nuked display output class support so we won't
be needing the respective headers for compilation on
backports now. This is as seen on next-20140409.

commit f167a64e9d67ebd03d304e369c12011cf2bffaf5
Author: Jean Delvare <jdelvare@suse.de>
Date:   Mon Mar 17 15:49:10 2014 +0100

    video / output: Drop display output class support

    It was only ever used by the ACPI video driver, and that only use case
    vanished over 3 years ago (see commit 677bd810, "ACPI video: remove
    output switching control".) So this is dead code and I guess we can
    remove it now.

    Signed-off-by: Jean Delvare <jdelvare@suse.de>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>