drm/i915: remove dead code

79e53945 ("DRM: i915: add mode setting
support") added those variables but never used them.

Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1456763047-28828-2-git-send-email-eric.engestrom@imgtec.com