pci: Use const for pci_find_device_id() etc.

These functions don't modify the device-ID struct that is passed in, so
mark the argument as const, so the data structure can be declared that
way. This allows it to be placed in the rodata section.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/include/pci.h b/include/pci.h
index 8e62235..9a8ba03 100644
--- a/include/pci.h
+++ b/include/pci.h
@@ -1064,7 +1064,7 @@
  * @devp:	Returns matching device if found
  * @return 0 if found, -ENODEV if not
  */
-int pci_bus_find_devices(struct udevice *bus, struct pci_device_id *ids,
+int pci_bus_find_devices(struct udevice *bus, const struct pci_device_id *ids,
 			 int *indexp, struct udevice **devp);
 
 /**
@@ -1076,7 +1076,7 @@
  * @devp:	Returns matching device if found
  * @return 0 if found, -ENODEV if not
  */
-int pci_find_device_id(struct pci_device_id *ids, int index,
+int pci_find_device_id(const struct pci_device_id *ids, int index,
 		       struct udevice **devp);
 
 /**