net/smc: remove sock_error detour in clc-functions

There is no need to store the return value in sk_err, if it is
afterwards cleared again with sock_error(). This patch sets the
return value directly. Just cleanup, no functional change.

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