act_mirred: Fix mirred_init_module error handling

If tcf_register_action failed, mirred_device_notifier
should be unregistered.

Fixes: 3b87956e ("net sched: fix race in mirred device removal")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>