Comment # 1 on bug 100305 from Chris Wilson

commit 83884e97e18739e3588c6467a210838099d42073
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Mar 21 17:16:03 2017 +0000

    Restore "lib: Open debugfs files for the given DRM device"

    This reverts commit 25fbae15262cf570e207e62f50e7c5233e06bc67, restoring
    commit 301ad44cdf1b868b1ab89096721da91fa8541fdc
    Author: Tomeu Vizoso <tomeu.vizoso@collabora.com>
    Date:   Thu Mar 2 10:37:11 2017 +0100

        lib: Open debugfs files for the given DRM device

    with fixes.

    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>