Revert "drm/i915/psr: Make idle_frames sensible again"

Revert "drm/i915/psr: Make idle_frames sensible again"

This reverts

commit 9a31cb1d8e69c8b214946d85e3a16a1bfe69aa70
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Wed May 18 18:47:12 2016 +0200

    drm/i915/psr: Make idle_frames sensible again

There are panels that needs 4 idle frames before entering PSR,
but VBT is unproperly set.

Also lately it was identified that idle frame count calculated at HW
can be off by 1, what makes the minimum of 2, at least.

Without the current vbt+1 we are with the risk of having HW calculating
0 idle frames and entering PSR when it shouldn't. Regardless the lack
of link training.

[Jani: there is some disagreement on the explanation, but the commit
regresses so revert it is.]

References: http://marc.info/?i=20160904191153.GA2328@light.dominikbrodowski.net
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Fixes: 9a31cb1d8e69 ("drm/i915/psr: Make idle_frames sensible again")
Cc: drm-intel-fixes@lists.freedesktop.org # v4.8-rc1+
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1473295351-8766-1-git-send-email-rodrigo.vivi@intel.com