forcedeth: fix non-constant printk warnings

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index 8b7f8b7..e3b7305 100644
--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -940,7 +940,7 @@
 		delaymax -= delay;
 		if (delaymax < 0) {
 			if (msg)
-				printk(msg);
+				printk("%s", msg);
 			return 1;
 		}
 	} while ((readl(base + offset) & mask) != target);