there's something wrong with uaudio@ohci on the usbmp branch.
this is the minimally working port of ohci to mpusb, and it works
with uaudio but is lacking many other changes, yet.
slightly closer, and still working with uaudio.
sync a couple more changes from the main branch, uaudio@ohci still works.
sync with main branch
partial sync with main branch
at little closer to the main branch.
mostly in sync with the branch here now.
merge a few more things from the main branch.  uaudio@ohci still works.
merge a few more changes from the main branch.
pull across a few more of the changes from the main branch.
sync usb_subr.c and usbdivar.h with the branch entirely, and most of
usbdi.c as well.