r8169: fix an if condition

There is an extra semi-colon so __rtl8169_set_features() is called every
time.

Fixes: 929a031dfd62 ('r8169: adjust __rtl8169_set_features')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Hayes Wang <hayeswang@realtek.com>--
Signed-off-by: David S. Miller <davem@davemloft.net>