of: EXPORT_SYMBOL_GPL of_property_read_u64_array

Make of_property_read_u64_array() available for modules as well. This was
missing from the patch which originally added the function.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/of/base.c

@@ -1303,6 +1303,7 @@ int of_property_read_u64_array(const struct device_node *np,
 	}
 	return 0;
 }
+EXPORT_SYMBOL_GPL(of_property_read_u64_array);
 
 /**
  * of_property_read_string - Find and read a string from a property