Add deprecation notices to ISA sound cards

ISA sound cards (and ISA itself) are long obsolete. NYCBUG dmesgd has
no entries for any of these devices after 2005.

Add deprecation notices to device attach routines and man pages for:

snd_ad1816 Analog Devices AD1816 SoundPort
snd_ess Ensoniq ESS
snd_gusc Gravis UltraSound
snd_mss Microsoft Sound System
snd_sbc Creative Sound Blaster

Reviewed by: cy, mav
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D34604