net/mlx5e: Return error in case mlx5e_set_features() fails

In case mlx5e_set_features() fails, return the failure status rather
than 0.

Signed-off-by: Achiad Shochat <achiad@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>