ACPI: property: Use ACPI functions in acpi_graph_get_next_endpoint() only

ACPI: property: Use ACPI functions in acpi_graph_get_next_endpoint() only

Calling fwnode_get_next_child_node() in ACPI implementation of the fwnode
property API is somewhat problematic as the latter is used in the
impelementation of the former. Instead of using
fwnode_get_next_child_node() in acpi_graph_get_next_endpoint(), call
acpi_get_next_subnode() directly instead.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20251001104320.1272752-3-sakari.ailus@linux.intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>