snd-firewire-lib: rename receive/transmit to in/out

The keyword "receive" and "transmit" are for the incarnation of devices in each
drivers. Then the keyword "in" and "out" should be used.
snd-fireworks/bebob: rename receive/transmit correctly

To keep naming consistency, rename some member in the incarnation of device.
Additionally for snd-fireworks, some members and functions related to MIDI are
removed.