CVE-2023-54112 kcm: Fix memory leak in error path of kcm_sendmsg()

In the Linux kernel, the following vulnerability has been resolved: kcm: Fix memory leak in error path of kcmsendmsg syzbot reported a memory leak like below: BUG: memory leak unreferenced object 0xffff88810b088c00 size 240: comm "syz-executor186", pid 5012, jiffies 4294943306 age 13.680s hex dum...