net/smc: remove unused parameter of smc_lgr_terminate()

The soft parameter of smc_lgr_terminate() is not used and obsolete.
Remove it.

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>