net/smc: use termination worker under send_lock

smc_tx_rdma_write() is called under the send_lock and should not call
smc_lgr_terminate() directly. Call smc_lgr_terminate_sched() instead
which schedules a worker.

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