gpio: shared: ignore special __symbols__ node when traversing device tree

The __symbols__ node is a special, internal node and its properties must
not be considered when scanning the device-tree for shared GPIOs.

Fixes: a060b8c ("gpiolib: implement low-level, shared GPIO support")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Closes: https://lore.kernel.org/all/0829a21c-f97d-41b6-90bc-2acaec42caab@nvidia.com/
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/20251126-gpio-shared-fixes-v1-1-18309c0e87b5@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: Bartosz Golaszewski

drivers/gpio/gpiolib-shared.c

@@ -73,6 +73,19 @@ gpio_shared_find_entry(struct fwnode_handle *controller_node,
 	return NULL;
 }
 
+/* Handle all special nodes that we should ignore. */
+static bool gpio_shared_of_node_ignore(struct device_node *node)
+{
+	/*
+	 * __symbols__ is a special, internal node and should not be considered
+	 * when scanning for shared GPIOs.
+	 */
+	if (of_node_name_eq(node, "__symbols__"))
+		return true;
+
+	return false;
+}
+
 static int gpio_shared_of_traverse(struct device_node *curr)
 {
 	struct gpio_shared_entry *entry;
@@ -84,6 +97,9 @@ static int gpio_shared_of_traverse(struct device_node *curr)
 	const char *suffix;
 	int ret, count, i;
 
+	if (gpio_shared_of_node_ignore(curr))
+		return 0;
+
 	for_each_property_of_node(curr, prop) {
 		/*
 		 * The standard name for a GPIO property is "foo-gpios"