Revert "drm/i915/bdw: BDW Software Turbo"

Revert "drm/i915/bdw: BDW Software Turbo"

This reverts commit c76bb61a71083b2d90504cc6d0dda2047c5d63ca.

It's apparently too broken so that Rodrigo submitted a patch to add a
config option for it. Given that the design is also ... suboptimal and
that I've only merged this to get lead engineers and managers off my
back for one second let's just revert this.

/me puts on combat gear again

It was worth a shot ...

References: http://mid.mail-archive.com/1411686380-1953-1-git-send-email-rodrigo.vivi@intel.com
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Daisy Sun <daisy.sun@intel.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>