If smc_wr_alloc_lgr_mem() fails then return an error code.  Don't return
success.

Fixes: 8799e310 ("net/smc: add v2 support to the work request layer")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>