net: ag71xx: Fix a potential double free in error handling paths

stable inclusion
from stable-v5.10.90
commit 7ef89bd1e8f1761cfd348d74150845eb57b7aa20
bugzilla: 186168 https://gitee.com/openeuler/kernel/issues/I4SHY1

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7ef89bd1e8f1761cfd348d74150845eb57b7aa20



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[ Upstream commit 1cd5384c ]

'ndev' is a managed resource allocated with devm_alloc_etherdev(), so there
is no need to call free_netdev() explicitly or there will be a double
free().

Simplify all error handling paths accordingly.

Fixes: d51b6ce4 ("net: ethernet: add ag71xx driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>