drm/i915/tv: Remove ->mode_set callback

Currently for the i9xx crtc hooks there's nothing between the call to
encoder->mode_set and encoder->pre_enable which touches the hardware.

Therefore, since tv is only used on gen3/4, we can just move the hook.
Yay for easy cases!

The only other important thing to check is that the new
->pre_enable hook is idempotent wrt the sw state since now it can
be called multiple times (due to DPMS). After a the bit of refactoring
this is now easy to check: It only reads crtc->config and computes
derived state but otherwise leaves it as-is, so we're good.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_tv.c

@@ -1013,7 +1013,7 @@ static void set_color_conversion(struct drm_i915_private *dev_priv,
 		   color_conversion->av);
 }
 
-static void intel_tv_mode_set(struct intel_encoder *encoder)
+static void intel_tv_pre_enable(struct intel_encoder *encoder)
 {
 	struct drm_device *dev = encoder->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -1632,7 +1632,7 @@ intel_tv_init(struct drm_device *dev)
 
 	intel_encoder->compute_config = intel_tv_compute_config;
 	intel_encoder->get_config = intel_tv_get_config;
-	intel_encoder->mode_set = intel_tv_mode_set;
+	intel_encoder->pre_enable = intel_tv_pre_enable;
 	intel_encoder->enable = intel_enable_tv;
 	intel_encoder->disable = intel_disable_tv;
 	intel_encoder->get_hw_state = intel_tv_get_hw_state;