Revert "drm/i915: Parsing LFP brightness control from VBT"

This reverts commit 371abae8.

This data seems unreliable and causing many issues and blocking other
teams and feature implementation. Safest way is to revert that for now.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88081
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88039
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=87671


Cc: Vandana Kannan <vandana.kannan@intel.com>
Cc: Deepak M <m.deepak@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Kristian Høgsberg <hoegsberg@gmail.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>