net/smc: keep clcsock reference in smc_tcp_listen_work()

The internal CLC socket should exist till the SMC-socket is released.
Function tcp_listen_worker() releases the internal CLC socket of a
listen socket, if an smc_close_active() is called. This function
is called for the final release(), but it is called for shutdown
SHUT_RDWR as well. This opens a door for protection faults, if
socket calls using the internal CLC socket are called for a
shutdown listen socket.

With the changes of
commit 3d502067 ("net/smc: simplify wait when closing listen socket")
there is no need anymore to release the internal CLC socket in
function tcp_listen_worker((). It is sufficient to release it in
smc_release().

Fixes: 127f4970 ("net/smc: release clcsock from tcp_listen_worker")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Reported-by:  <syzbot+9045fc589fcd196ef522@syzkaller.appspotmail.com>
Reported-by:  <syzbot+28a2c86cf19c81d871fa@syzkaller.appspotmail.com>
Reported-by:  <syzbot+9605e6cace1b5efd4a0a@syzkaller.appspotmail.com>
Reported-by:  <syzbot+cf9012c597c8379d535c@syzkaller.appspotmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>