net: phy: dp83867: Set FORCE_LINK_GOOD to default after reset

According to the Datasheet this bit should be 0 (Normal operation) in
default. With the FORCE_LINK_GOOD bit set, it is not possible to get a
link. This patch sets FORCE_LINK_GOOD to the default value after
resetting the phy.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>