media: intel/ipu6: fix async notifier cleanup leak on parse error

isys_notifier_init() calls v4l2_async_nf_init() and then adds fwnode
remote subdevs in a loop with v4l2_async_nf_add_fwnode_remote(). If an
endpoint parse or add fails partway through the loop, it jumps to
err_parse and returns without calling v4l2_async_nf_cleanup(), leaking
every v4l2_async_connection already added to the notifier's waiting
list.

The register-failure path just below already cleans up correctly, and
the caller only tears the notifier down (isys_notifier_cleanup()) once
isys_notifier_init() has returned success. Clean up the notifier on the
parse error path too.

Fixes: f50c4ca0a8 ("media: intel/ipu6: add the main input system driver")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4
Signed-off-by: Cong Nguyen <congnt264@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

drivers/media/pci/intel/ipu6/ipu6-isys.c

@@ -761,6 +761,7 @@ static int isys_notifier_init(struct ipu6_isys *isys)
 
 err_parse:
 		fwnode_handle_put(ep);
+		v4l2_async_nf_cleanup(&isys->notifier);
 		return ret;
 	}