net: phy: mscc: coma mode disabled for VSC8514

The 'coma mode' (configurable through sw or hw) provides an
optional feature that may be used to control when the PHYs become active.
The typical usage is to synchronize the link-up time across
all PHY instances. This patch releases coma mode if not done by hardware,
otherwise the phys will not link-up.

Fixes: e4f9ba64 ("net: phy: mscc: add support for VSC8514 PHY.")
Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
Signed-off-by: Bjarni Jonasson <bjarni.jonasson@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>