IB/core: Fix error return code in add_port()

Fix to return -ENOMEM in the add_port() error handling case instead of
0, as done elsewhere in this function.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Roland Dreier <roland@purestorage.com>
1 file changed