ACPI: Normalize return value of resource parser functions

Normalize return value of resource parse functions as:
1) return "true" if resource is assigned.
2) return "false" and IORESOURCE_DISABLED setting in res->flags if
   resource is unassigned.
3) return "false" and zeroing res->flags if it's not an valid or
   expected resource.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>