core: ofnode_graph: Fix a comment

Naming between the parameter list, the prototype and the main comment do
not match. Fix the comment which seems the be the one that is incorrect.

Fixes: 9057077cf4 ("core: ofnode: add of_graph parsing helpers")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Svyatoslav Ryhel <clamor95@gmail.com>

drivers/core/ofnode_graph.c

@@ -98,7 +98,7 @@ ofnode ofnode_graph_get_port_by_id(ofnode parent, u32 id)
  * @id: id for the endpoint
  *
  * Return: ofnode in given endpoint or ofnode_null() if not found.
- * reg and port_reg are ignored when they are -1.
+ * reg_id and id are ignored when they are -1.
  */
 ofnode ofnode_graph_get_endpoint_by_regs(ofnode parent, int reg_id, int id)
 {