Fix to return a negative error code from the error handling
case instead of 0, as done elsewhere in this function.

Fixes: 2bb4b98b ("net: stmmac: Add Ingenic SoCs MAC support.")
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>