ide: constify struct ide_port_info

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/it821x.c b/drivers/ide/pci/it821x.c
index 06bd576..1a7ddd1 100644
--- a/drivers/ide/pci/it821x.c
+++ b/drivers/ide/pci/it821x.c
@@ -638,7 +638,7 @@
 		.pio_mask	= ATA_PIO4,		\
 	}
 
-static struct ide_port_info it821x_chipsets[] __devinitdata = {
+static const struct ide_port_info it821x_chipsets[] __devinitdata = {
 	/* 0 */ DECLARE_ITE_DEV("IT8212"),
 };