RDMA/nes: Slight optimization of Ethernet address compare

Use the possibly more efficient ether_addr_equal() instead of memcmp().

Signed-off-by: Wang Weidong <wangweidong1@huawei.com>
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>