ACPI/PNP: A HID value of an object never changes -> make it const

Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/pnp/driver.c b/drivers/pnp/driver.c
index cd11b11..d1dbb9d 100644
--- a/drivers/pnp/driver.c
+++ b/drivers/pnp/driver.c
@@ -236,7 +236,7 @@
  * @dev: pointer to the desired device
  * @id: pointer to an EISA id string
  */
-struct pnp_id *pnp_add_id(struct pnp_dev *dev, char *id)
+struct pnp_id *pnp_add_id(struct pnp_dev *dev, const char *id)
 {
 	struct pnp_id *dev_id, *ptr;