cassini: fix off by one

There are only 6 link_modes.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/cassini.c b/drivers/net/cassini.c
index 7cbcfb0..9bd155e 100644
--- a/drivers/net/cassini.c
+++ b/drivers/net/cassini.c
@@ -5072,7 +5072,7 @@
 	INIT_WORK(&cp->reset_task, cas_reset_task);
 
 	/* Default link parameters */
-	if (link_mode >= 0 && link_mode <= 6)
+	if (link_mode >= 0 && link_mode < 6)
 		cp->link_cntl = link_modes[link_mode];
 	else
 		cp->link_cntl = BMCR_ANENABLE;