It's not necessary to free netdev allocated with devm_alloc_etherdev()
and using free_netdev() leads to double free.

Fixes: fd3040b9 ("net: ethernet: Add driver for Sunplus SP7021")
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20221109150116.2988194-1-weiyongjun@huaweicloud.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>