sound: Add min_rate and min_channels safety check in SNDCTL_AUDIOINFO

If the channel list is empty, min_rate and min_channels will be INT_MAX.
Instead, assign them to 0, like we do in sndstat_get_caps().

Sponsored by: The FreeBSD Foundation
MFC after: 2 days
Reviewed by: dev_submerge.ch
Differential Revision: https://reviews.freebsd.org/D45876