ide: constify struct ide_port_info

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/pci/slc90e66.c b/drivers/ide/pci/slc90e66.c
index 9352d0c..c457bf4 100644
--- a/drivers/ide/pci/slc90e66.c
+++ b/drivers/ide/pci/slc90e66.c
@@ -146,7 +146,7 @@
 		hwif->cbl = (reg47 & mask) ? ATA_CBL_PATA40 : ATA_CBL_PATA80;
 }
 
-static struct ide_port_info slc90e66_chipset __devinitdata = {
+static const struct ide_port_info slc90e66_chipset __devinitdata = {
 	.name		= "SLC90E66",
 	.init_hwif	= init_hwif_slc90e66,
 	.enablebits	= {{0x41,0x80,0x80}, {0x43,0x80,0x80}},