net: amd: Fix link leak when verifying config failed

After failing to verify configuration, it returns directly without
releasing link, which may cause memory leak.

Paolo Abeni thinks that the whole code of this driver is quite
"suboptimal" and looks unmainatained since at least ~15y, so he
suggests that we could simply remove the whole driver, please
take it into consideration.

Simon Horman suggests that the fix label should be set to
"Linux-2.6.12-rc2" considering that the problem has existed
since the driver was introduced and the commit above doesn't
seem to exist in net/net-next.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Gan Gecen <gangecen@hust.edu.cn>
Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>