of: dynamic: Fix potential memory leak in of_changeset_action()

Smatch complains that the error path where "action" is invalid leaks
the "ce" allocation:
    drivers/of/dynamic.c:935 of_changeset_action()
    warn: possible memory leak of 'ce'

Fix this by doing the validation before the allocation.

Note that there is not any actual problem with upstream kernels. All
callers of of_changeset_action() are static inlines with fixed action
values.

Fixes: 914d9d8 ("of: dynamic: Refactor action prints to not use "%pOF" inside devtree_lock")
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]/
Signed-off-by: Dan Carpenter <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Rob Herring <[email protected]>

Author: Dan Carpenter

drivers/of/dynamic.c

@@ -890,13 +890,13 @@ int of_changeset_action(struct of_changeset *ocs, unsigned long action,
 {
 	struct of_changeset_entry *ce;
 
+	if (WARN_ON(action >= ARRAY_SIZE(action_names)))
+		return -EINVAL;
+
 	ce = kzalloc(sizeof(*ce), GFP_KERNEL);
 	if (!ce)
 		return -ENOMEM;
 
-	if (WARN_ON(action >= ARRAY_SIZE(action_names)))
-		return -EINVAL;
-
 	/* get a reference to the node */
 	ce->action = action;
 	ce->np = of_node_get(np);