via-velocity: fix the WOL bug on 1000M full duplex forced mode.

The VIA velocity card can't be waken up by WOL tool on 1000M full
duplex forced mode. This patch fixes the bug.

Signed-off-by: David Lv <DavidLv@viatech.com.cn>
Acked-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>