drm/i915: rip out encoder->prepare/commit

With the new infrastructure we're doing this when enabling/disabling
the entire display pipe.

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_sdvo.c

@@ -1889,9 +1889,7 @@ done:
 
 static const struct drm_encoder_helper_funcs intel_sdvo_helper_funcs = {
 	.mode_fixup = intel_sdvo_mode_fixup,
-	.prepare = intel_encoder_noop,
 	.mode_set = intel_sdvo_mode_set,
-	.commit = intel_encoder_noop,
 	.disable = intel_encoder_disable
 };