drm/i915: drop WaSetupGtModeTdRowDispatch:snb

This reverts the regressing

commit 6547fbdb
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Dec 14 23:38:29 2012 +0100

    drm/i915: Implement WaSetupGtModeTdRowDispatch

that causes GPU hangs immediately on boot.

Reported-by: Leo Wolf <jclw@ymail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79996


Cc: stable@vger.kernel.org (v3.8+)
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
[Jani: amended the commit message slightly.]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>