panic after new device layering commit

[Matthew Dillon]

:panic: impossible devtype 0
:
:It paniced at dsp_open, I will get a backtrace. Since it happened at
:dsp_open, I'll check out if I can trigger this panic again.
:
:Cheers,
:Emiel

    I believe I have fixed this issue, but my test box doesn't appear to
    have a sound devie that DFly recognizes so I can't test it other then
    to verify that the various sound devices are not trampling each other's
    cdevsw's any longer.

					-Matt
					Matthew Dillon 
					<dillon at xxxxxxxxxxxxx>