dm: core: Allow finding children / uclasses by partial name

In some cases it is useful to search just by a partial name, such as
when looking for a sibling device that has a common name substring. Add
helper functions to handle these requirements.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/dm/device.h b/include/dm/device.h
index 3028d00..daf28a0 100644
--- a/include/dm/device.h
+++ b/include/dm/device.h
@@ -763,6 +763,18 @@
  *
  * @parent:	Parent device to search
  * @name:	Name to look for
+ * @len:	Length of the name
+ * @devp:	Returns device found, if any
+ * @return 0 if found, else -ENODEV
+ */
+int device_find_child_by_namelen(const struct udevice *parent, const char *name,
+				 int len, struct udevice **devp);
+
+/**
+ * device_find_child_by_name() - Find a child by device name
+ *
+ * @parent:	Parent device to search
+ * @name:	Name to look for
  * @devp:	Returns device found, if any
  * @return 0 if found, else -ENODEV
  */