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_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 93fc8ab..8e3aad0 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -123,8 +123,8 @@
 }
 
 static void intel_mst_disable_dp(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_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
 	struct intel_digital_port *intel_dig_port = intel_mst->primary;
@@ -146,8 +146,8 @@
 }
 
 static void intel_mst_post_disable_dp(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_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
 	struct intel_digital_port *intel_dig_port = intel_mst->primary;
@@ -176,8 +176,8 @@
 }
 
 static void intel_mst_pre_enable_dp(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_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
 	struct intel_digital_port *intel_dig_port = intel_mst->primary;
@@ -219,8 +219,8 @@
 }
 
 static void intel_mst_enable_dp(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_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
 	struct intel_digital_port *intel_dig_port = intel_mst->primary;