ACPI: sony-laptop.c: call acpi_get_object_info to get node info

Avoid using internal acpica structures acpi_namespace_node and acpi_operand_object
Call acpi_get_object_info to get node ascii name and method arg count

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>