net: ethernet: aquantia: remove another redundant err check

The check on err < 0 is redundant and can be removed. Detected
by CoverityScan, CID#1398318 ("Logically Dead Code")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed