sound: Fix min/max rate for SNDCTL_AUDIOINFO and SNDCTL_ENGINEINFO

Since we allow feeding of any rate within the [feeder_rate_min,
feeder_rate_max] range, report this as the min/max rate as well. Only
exceptions are when we the device is opened in exclusive or bitperfect
mode.

Sponsored by: The FreeBSD Foundation
MFC after: 2 days
Reviewed by: dev_submerge.ch
Differential Revision: https://reviews.freebsd.org/D45862

(cherry picked from commit 86585210fd5657542884b22eb52b21e960b7be6c)