drm/i915: Constify watermark state checker

The skl+ wm state checker has no reason to modify the crtc state,
so make it const.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231004155607.7719-6-ville.syrjala@linux.intel.comReviewed-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/i915/display/skl_watermark.c

@@ -3135,7 +3135,7 @@ static void skl_wm_get_hw_state_and_sanitize(struct drm_i915_private *i915)
 }
 
 void intel_wm_state_verify(struct intel_crtc *crtc,
-			   struct intel_crtc_state *new_crtc_state)
+			   const struct intel_crtc_state *new_crtc_state)
 {
 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
 	struct skl_hw_state {

drivers/gpu/drm/i915/display/skl_watermark.h

@@ -39,7 +39,7 @@ bool skl_ddb_allocation_overlaps(const struct skl_ddb_entry *ddb,
 				 int num_entries, int ignore_idx);
 
 void intel_wm_state_verify(struct intel_crtc *crtc,
-			   struct intel_crtc_state *new_crtc_state);
+			   const struct intel_crtc_state *new_crtc_state);
 
 void skl_watermark_ipc_init(struct drm_i915_private *i915);
 void skl_watermark_ipc_update(struct drm_i915_private *i915);