net: freescale: remove unused compare_addr()

The function did not be used any more, so remove it.

Cc: Li Yang <leoli@freescale.com>
Cc: netdev@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>