gianfar: correct filer table writing

MAX_FILER_IDX is the last usable index.  Using less-than
will already guarantee that one entry for catch-all rule
will be left, no need to subtract 1 here.
Signed-off-by: NJakub Kicinski <kubakici@wp.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/freescale/gianfar_ethtool.c

@@ -1583,11 +1583,10 @@ static int gfar_write_filer_table(struct gfar_private *priv,
 		return -EBUSY;
 
 	/* Fill regular entries */
-	for (; i < MAX_FILER_IDX - 1 && (tab->fe[i].ctrl | tab->fe[i].prop);
-	     i++)
+	for (; i < MAX_FILER_IDX && (tab->fe[i].ctrl | tab->fe[i].prop); i++)
 		gfar_write_filer(priv, i, tab->fe[i].ctrl, tab->fe[i].prop);
 	/* Fill the rest with fall-troughs */
-	for (; i < MAX_FILER_IDX - 1; i++)
+	for (; i < MAX_FILER_IDX; i++)
 		gfar_write_filer(priv, i, 0x60, 0xFFFFFFFF);
 	/* Last entry must be default accept
 	 * because that's what people expect