drm/i915: Use mode_config->cursor_width for cursor DDB allocation

Replace the hardcoded 256 with mode_config->cursor_width
when doing the cursor DDB allocation. Currently 256 is correct
for all SKL+, but this might change in the future. One less place
to change should that happen.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20251107181126.5743-8-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

Author: vsyrjala

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

@@ -635,6 +635,7 @@ skl_cursor_allocation(const struct intel_crtc_state *crtc_state,
 {
 	struct intel_display *display = to_intel_display(crtc_state);
 	struct intel_plane *plane = to_intel_plane(crtc_state->uapi.crtc->cursor);
+	const struct drm_mode_config *mode_config = &display->drm->mode_config;
 	const struct drm_format_info *info;
 	struct skl_wm_level wm = {};
 	int ret, min_ddb_alloc = 0;
@@ -648,7 +649,7 @@ skl_cursor_allocation(const struct intel_crtc_state *crtc_state,
 
 	info  = drm_get_format_info(display->drm, format, modifier);
 
-	ret = skl_compute_wm_params(crtc_state, 256,
+	ret = skl_compute_wm_params(crtc_state, mode_config->cursor_width,
 				    info, modifier, DRM_MODE_ROTATE_0,
 				    crtc_state->pixel_rate, &wp, 0, 0);
 	drm_WARN_ON(display->drm, ret);