of: Fix of_graph_parse_endpoint stub for !CONFIG_OF builds
This patch fixes the following build error:
In file included from drivers/media/i2c/adv7343.c:29:0:
>> include/linux/of_graph.h:41:1: error: expected identifier or '(' before '{' token
{
^
include/linux/of_graph.h:39:19: warning: 'of_graph_parse_endpoint' declared 'static' but never defined [-Wunused-function]
static inline int of_graph_parse_endpoint(const struct device_node *node,
^