net: ethernet: sun: remove redundant assignment to variable err

The variable err is being assigned with a value that is never
read and it is being updated in the next statement with a new value.
The assignment is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/sun/niu.c

@@ -1217,8 +1217,6 @@ static int link_status_1g_rgmii(struct niu *np, int *link_up_p)
 
 	spin_lock_irqsave(&np->lock, flags);
 
-	err = -EINVAL;
-
 	err = mii_read(np, np->phy_addr, MII_BMSR);
 	if (err < 0)
 		goto out;