drm/i915: Constify states passed to enable/disable/etc. encoder hooks

The enable/disable/etc. encoder hooks aren't supposed to alter the
state(s), so pass them as const. Unfortunately C lacks any kind of deep
const thingy, so this can't catch all abuses. But at least it acts as a
hint to the reader telling them not to mess about with the state(s).

v2: Update intel_tv_mode_find() and ironlake_edp_pll_on() as well
v3: Deal with intel_sdvo_connector_state

Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170818134958.15502-9-ville.syrjala@linux.intel.com
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 8e21577..a9813ae 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -229,8 +229,8 @@ static void intel_lvds_pps_init_hw(struct drm_i915_private *dev_priv,
 }
 
 static void intel_pre_enable_lvds(struct intel_encoder *encoder,
-				  struct intel_crtc_state *pipe_config,
-				  struct drm_connector_state *conn_state)
+				  const struct intel_crtc_state *pipe_config,
+				  const struct drm_connector_state *conn_state)
 {
 	struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
@@ -306,8 +306,8 @@ static void intel_pre_enable_lvds(struct intel_encoder *encoder,
  * Sets the power state for the panel.
  */
 static void intel_enable_lvds(struct intel_encoder *encoder,
-			      struct intel_crtc_state *pipe_config,
-			      struct drm_connector_state *conn_state)
+			      const struct intel_crtc_state *pipe_config,
+			      const struct drm_connector_state *conn_state)
 {
 	struct drm_device *dev = encoder->base.dev;
 	struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
@@ -324,8 +324,8 @@ static void intel_enable_lvds(struct intel_encoder *encoder,
 }
 
 static void intel_disable_lvds(struct intel_encoder *encoder,
-			       struct intel_crtc_state *old_crtc_state,
-			       struct drm_connector_state *old_conn_state)
+			       const struct intel_crtc_state *old_crtc_state,
+			       const struct drm_connector_state *old_conn_state)
 {
 	struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
@@ -339,8 +339,8 @@ static void intel_disable_lvds(struct intel_encoder *encoder,
 }
 
 static void gmch_disable_lvds(struct intel_encoder *encoder,
-			      struct intel_crtc_state *old_crtc_state,
-			      struct drm_connector_state *old_conn_state)
+			      const struct intel_crtc_state *old_crtc_state,
+			      const struct drm_connector_state *old_conn_state)
 
 {
 	intel_panel_disable_backlight(old_conn_state);
@@ -349,15 +349,15 @@ static void gmch_disable_lvds(struct intel_encoder *encoder,
 }
 
 static void pch_disable_lvds(struct intel_encoder *encoder,
-			     struct intel_crtc_state *old_crtc_state,
-			     struct drm_connector_state *old_conn_state)
+			     const struct intel_crtc_state *old_crtc_state,
+			     const struct drm_connector_state *old_conn_state)
 {
 	intel_panel_disable_backlight(old_conn_state);
 }
 
 static void pch_post_disable_lvds(struct intel_encoder *encoder,
-				  struct intel_crtc_state *old_crtc_state,
-				  struct drm_connector_state *old_conn_state)
+				  const struct intel_crtc_state *old_crtc_state,
+				  const struct drm_connector_state *old_conn_state)
 {
 	intel_disable_lvds(encoder, old_crtc_state, old_conn_state);
 }