net: phy: initialize rc to zero to avoid returning garbage value

In the case where phydev->interrupts is not PHY_INTERRUPT_ENABLED
function vsc85xx_ack_interrupt is returning an uninitialized
garbage value.  Fix this by initializing rc to zero.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/mscc.c

@@ -84,7 +84,7 @@ static int vsc85xx_config_init(struct phy_device *phydev)
 
 static int vsc85xx_ack_interrupt(struct phy_device *phydev)
 {
-       int rc;
+       int rc = 0;
 
        if (phydev->interrupts == PHY_INTERRUPT_ENABLED)
                rc = phy_read(phydev, MII_VSC85XX_INT_STATUS);