Replace audio(9) get_props() with duplex check in open() in non-duplex drivers

Replace audio(9) get_props() with duplex check in open() in non-duplex drivers

Make drivers which do *not* adverise AUDIO_PROP_FULLDPLEX return ENXIO
in their open() if full-duplex mode was requested.

This way, sys/dev/audio.c:audio_open() will fail immediately rather than
later through the to-be-removed get_props() check.

These are all drivers which simply don't support full-duplex mode.

In device-tree based drivers like simpleaudio(4)/rkiis(4) and newer Apple
ones like aplaudio(4)/aplmca(4), this adds a new open() stub to the
low-level drivers which merely does the duplex check.

My Pinebook Pro keeps playing audio and recording silence with this diff
just like before (rkiis(4) is currently play-only):
	simpleaudio0 at mainbus0
	simpleaudio1 at mainbus0
	audio0 at simpleaudio1

	$ aucat -i song69.wav -o rec.wav

OK ratchov miod