fbdev/atyfb: fix recent breakage in correct_chipset()

The 6e36308a "fb: fix atyfb build warning" isn't right.  It makes all
the indexes off by one.  This patch reverts it and casts the
ARRAY_SIZE() to int to silence the build warning.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/aty/atyfb_base.c

@@ -435,8 +435,8 @@ static int correct_chipset(struct atyfb_par *par)
 	const char *name;
 	int i;
 
-	for (i = ARRAY_SIZE(aty_chips); i > 0; i--)
-		if (par->pci_id == aty_chips[i - 1].pci_id)
+	for (i = (int)ARRAY_SIZE(aty_chips) - 1; i >= 0; i--)
+		if (par->pci_id == aty_chips[i].pci_id)
 			break;
 
 	if (i < 0)