Provide an ioctl to set the SCO mtu value in the controller and
place limits in the SCO code such that only packets of this size
may be sent.
Move the mtu option from btsco(4) and btdevctl(8), to the
btconfig(8) program.
Remove temporary BLUETOOTH_SCO kernel option, and enable SCO
socket access.
Fix incoming connection handling for btsco(4) and SCO sockets.
Fix documentation to reflect the new world order.