ACPICA: Add NHLT table signature

ACPICA commit 422166b656565d180bb3aac712009bdce5e70cdd

NHLT (Non-HDAudio Link Table) provides configuration of audio
endpoints for Intel SST (Smart Sound Technology) DSP products.
Similarly to other ACPI tables, data provided by BIOS may not
describe it correctly, thus overriding is required.

ACPI override mechanism checks for unknown signature before
proceeding. Update known signatures array to support NHLT.

Link: https://github.com/acpica/acpica/commit/422166b6


Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>