ACPI: x86: s2idle: Switch to use acpi_evaluate_dsm_typed()

The acpi_evaluate_dsm_typed() provides a way to check the type of the
object evaluated by _DSM call. Use it instead of open coded variant.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>