dm: core: Expand integer-reading tests

The current tests do not cover all the behaviour. Add some more.

Tidy up a few inconsistencies between livetree and flattree which come to
light with these tests. Also drop the -ENODATA error since it is never
actually returned.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/dm/of_access.h b/include/dm/of_access.h
index dd70b44..c556a18 100644
--- a/include/dm/of_access.h
+++ b/include/dm/of_access.h
@@ -327,8 +327,7 @@
  * @outp:	pointer to return value, modified only if return value is 0.
  *
  * Return:
- *   0 on success, -EINVAL if the property does not exist,
- *   -ENODATA if property does not have a value, and -EOVERFLOW if the
+ *   0 on success, -EINVAL if the property does not exist, or -EOVERFLOW if the
  *   property data isn't large enough.
  */
 int of_read_u32_index(const struct device_node *np, const char *propname,
@@ -345,8 +344,7 @@
  * @outp:	pointer to return value, modified only if return value is 0.
  *
  * Return:
- *   0 on success, -EINVAL if the property does not exist,
- *   -ENODATA if property does not have a value, and -EOVERFLOW if the
+ *   0 on success, -EINVAL if the property does not exist, or -EOVERFLOW if the
  *   property data isn't large enough.
  */
 int of_read_u64(const struct device_node *np, const char *propname, u64 *outp);
@@ -362,8 +360,8 @@
  * @out_values:	pointer to return value, modified only if return value is 0.
  * @sz:		number of array elements to read
  * Return:
- *   0 on success, -EINVAL if the property does not exist, -ENODATA
- *   if property does not have a value, and -EOVERFLOW is longer than sz.
+ *   0 on success, -EINVAL if the property does not exist, or -EOVERFLOW if
+ *   longer than sz.
  */
 int of_read_u32_array(const struct device_node *np, const char *propname,
 		      u32 *out_values, size_t sz);