Revert "drm/i915: skip modeset if compatible for everyone."

Revert "drm/i915: skip modeset if compatible for everyone."

This reverts

commit 6764e9f8724f1231b4deac53b9a82286ac0830e7
Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date:   Thu Aug 27 15:44:06 2015 +0200

    drm/i915: skip modeset if compatible for everyone.

Bring back the i915.fastboot module parameter, disabled by default, due
to backlight regression on Chromebook Pixel 2015.

Apparently the firmware of the Chromebook in question enables the panel
but disables backlight to avoid a brief garbage scanout upon loading the
kernel/module. With fastboot, we leave the backlight untouched, in this
case disabled. The user would have to do a modeset (i.e. not just crank
up the brightness) to enable the backlight.

There is no clean fix readily available, so get back to the drawing
board by reverting.

[N.B. The reference below is for when the thread was included on public
lists, and some of the context had already been dropped by then.]

Reported-and-tested-by: Olof Johansson <olof@lixom.net>
Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
References: http://marc.info/?i=CAKMK7uES7xk05ki92oeX6gmvZWAh9f2vL7yz=6T+fGK9J3X7cQ@mail.gmail.com
Fixes: 6764e9f8724f ("drm/i915: skip modeset if compatible for everyone.")
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1447921590-3785-1-git-send-email-jani.nikula@intel.com