alsa: more tapdancing to enumerate physical hardware devices.

Apparently some systems see "hw:", some see "default:" and some see
"sysdefault:" (and maybe others!). My workstation sees both "hw:" and
"sysdefault:" ...

Try to find a prefix we like and prioritize the prefixes we (think) we want
most. If everything else fails, if there's a "default" (not a prefix) device
name, list that by itself so the user gets _something_ here.

If we can't find a prefix we like _and_ there's no "default" device, report
no hardware found at all.
1 file changed