snd_hda: Default to 256 when corb/rirb is invalid
PR: 289284
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Reviewed by: emaste
Differential Revision: https://reviews.freebsd.org/D54339
(cherry picked from commit 2455db44ef088797d113397f863d46c50e77134f)