net/smc: cleanup tcp_listen_worker initialization

The tcp_listen_worker is already initialized when socket is
created (in smc_sock_alloc()). Get rid of the duplicate
initialization in smc_listen(). No functional change.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>