drm/i915/wm: Verify the correct plane DDB entry

[ Upstream commit a97c88a ]

Actually verify the DDB entry for the plane we're looking
at instead of always verifying the cursor DDB.

Fixes: 7d45617 ("drm/i915: Tweak plane ddb allocation tracking")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patch.msgid.link/20260324134843.2364-5-ville.syrjala@linux.intel.com
Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
(cherry picked from commit f002f7c)
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: vsyrjala

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

@@ -3980,8 +3980,8 @@ void intel_wm_state_verify(struct intel_atomic_state *state,
 		}
 
 		/* DDB */
-		hw_ddb_entry = &hw->ddb[PLANE_CURSOR];
-		sw_ddb_entry = &new_crtc_state->wm.skl.plane_ddb[PLANE_CURSOR];
+		hw_ddb_entry = &hw->ddb[plane->id];
+		sw_ddb_entry = &new_crtc_state->wm.skl.plane_ddb[plane->id];
 
 		if (!skl_ddb_entry_equal(hw_ddb_entry, sw_ddb_entry)) {
 			drm_err(display->drm,