add aciodrv-proc module
explanation : PANB works differently from other acio devices ; you send
one "start auto input" command without expecting a reply, and then the
piano keeps spamming "recv poll" commands on the acio bus and never replies
to any other commands.. failure to process these messages quickly enough
will saturate the serial buffer and cause checksum errors after a while.
for this reason, aciodrv-proc module was added in order to create a
thread which manages these recv poll commands and keeps the latest
known button state in memory so that it can be retrieved easily.
Matryoshka