drm/i915/wm: clear the plane ddb_y entries on plane disable

The UV/Y plane DDB entriess are never cleared on
sk_wm_plane_disable_noatomic() and can leave stale DDB state
for NV12 planes on pre-Gen11 devices

Fixes: d34b59d ("drm/i915: Add skl_wm_plane_disable_noatomic()")
Assisted-by: Copilot:claude-sonnet-4.6
Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patch.msgid.link/20260615203355.218578-2-vinod.govindapillai@intel.com
(cherry picked from commit 60f68a6)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Author: vgovind2

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

@@ -3856,7 +3856,7 @@ void skl_wm_plane_disable_noatomic(struct intel_crtc *crtc,
 		return;
 
 	skl_ddb_entry_init(&crtc_state->wm.skl.plane_ddb[plane->id], 0, 0);
-	skl_ddb_entry_init(&crtc_state->wm.skl.plane_ddb[plane->id], 0, 0);
+	skl_ddb_entry_init(&crtc_state->wm.skl.plane_ddb_y[plane->id], 0, 0);
 
 	crtc_state->wm.skl.plane_min_ddb[plane->id] = 0;
 	crtc_state->wm.skl.plane_interim_ddb[plane->id] = 0;