ACPI / utils: Fix memory leak in acpi_evaluate_reference() error path

When package.count is larger than ACPI_MAX_HANDLES, buffer.pointer is
not freed before the function returns AE_NO_MEMORY. Fix this possible
memory leak by kfree'ing it.

Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>