dt: add helper function to read u32 arrays

Rework of_property_read_u32 to read an array of values. Then
of_property_read_u32 becomes an inline with array size of 1.

Also make struct device_node ptr const.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/include/linux/of.h b/include/linux/of.h
index b238520..b5f1c88 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -195,8 +195,18 @@
 extern struct property *of_find_property(const struct device_node *np,
 					 const char *name,
 					 int *lenp);
-extern int of_property_read_u32(struct device_node *np, char *propname,
-					u32 *out_value);
+extern int of_property_read_u32_array(const struct device_node *np,
+				      char *propname,
+				      u32 *out_values,
+				      size_t sz);
+
+static inline int of_property_read_u32(const struct device_node *np,
+				       char *propname,
+				       u32 *out_value)
+{
+	return of_property_read_u32_array(np, propname, out_value, 1);
+}
+
 extern int of_property_read_string(struct device_node *np, char *propname,
 					const char **out_string);
 extern int of_device_is_compatible(const struct device_node *device,