ide: constify struct ide_port_info

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/opti621.c b/drivers/ide/pci/opti621.c
index 6152738..8d28f33 100644
--- a/drivers/ide/pci/opti621.c
+++ b/drivers/ide/pci/opti621.c
@@ -331,7 +331,7 @@
 	hwif->set_pio_mode = &opti621_set_pio_mode;
 }
 
-static struct ide_port_info opti621_chipsets[] __devinitdata = {
+static const struct ide_port_info opti621_chipsets[] __devinitdata = {
 	{	/* 0 */
 		.name		= "OPTI621",
 		.init_hwif	= init_hwif_opti621,