of: define of_find_node_by_phandle for !CONFIG_OF

Define stub implementation for of_find_node_by_phandle() API
so that users of this API can build properly even when CONFIG_OF
is not defined.

Fixes x86 randconfig build failure of remoteproc.
Signed-off-by: Suman Anna <s-anna@ti.com>
[robh: add details on fixing remoteproc compile]
Signed-off-by: Rob Herring <robh@kernel.org>

include/linux/of.h

@@ -422,6 +422,11 @@ static inline struct device_node *of_find_node_opts_by_path(const char *path,
 	return NULL;
 }
 
+static inline struct device_node *of_find_node_by_phandle(phandle handle)
+{
+	return NULL;
+}
+
 static inline struct device_node *of_get_parent(const struct device_node *node)
 {
 	return NULL;