CVE-2021-47598 sch_cake: do not call cake_destroy() from cake_init()

In the Linux kernel, the following vulnerability has been resolved: schcake: do not call cakedestroy from cakeinit qdiscs are not supposed to call their own destroy method from init, because core stack already does that. syzbot was able to trigger use after free: DEBUGLOCKSWARNONlock-magic != loc...