pinctrl: core: handle radix_tree_insert() errors in pinctrl_generic_add_group()

pinctrl_generic_add_group() doesn't check the result of radix_tree_insert()
despite they both may return a negative error code.  Linus Walleij said he
has copied the radix tree code from kernel/irq/ where the functions calling
radix_tree_insert() are *void* themselves; I think it makes more sense to
propagate the errors from radix_tree_insert() upstream if we can do that...

Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://lore.kernel.org/r/20230719202253.13469-2-s.shtylyov@omp.ruSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/core.c

@@ -633,7 +633,7 @@ int pinctrl_generic_add_group(struct pinctrl_dev *pctldev, const char *name,
 			      int *pins, int num_pins, void *data)
 {
 	struct group_desc *group;
-	int selector;
+	int selector, error;
 
 	if (!name)
 		return -EINVAL;
@@ -653,7 +653,9 @@ int pinctrl_generic_add_group(struct pinctrl_dev *pctldev, const char *name,
 	group->num_pins = num_pins;
 	group->data = data;
 
-	radix_tree_insert(&pctldev->pin_group_tree, selector, group);
+	error = radix_tree_insert(&pctldev->pin_group_tree, selector, group);
+	if (error)
+		return error;
 
 	pctldev->num_groups++;