dm: pci: Add a driver-model version of pci_find_class()

Add a function which scans the driver model device information rather
than scanning the PCI bus again.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/include/pci.h b/include/pci.h
index 347dd0a..443af83 100644
--- a/include/pci.h
+++ b/include/pci.h
@@ -1179,6 +1179,16 @@
 		       struct udevice **devp);
 
 /**
+ * dm_pci_find_class() - find a device by class
+ *
+ * @find_class: 3-byte (24-bit) class value to find
+ * @index:	0 to find the first match, 1 for second, etc.
+ * @devp:	Returns pointer to the device, if found
+ * @return 0 if found, -ve on error
+ */
+int dm_pci_find_class(uint find_class, int index, struct udevice **devp);
+
+/**
  * struct dm_pci_emul_ops - PCI device emulator operations
  */
 struct dm_pci_emul_ops {