firewire-lib: add read and channel map for dualwire mode support

Dice chipset has a mode named as 'dualwire' for its streaming with high sampling
rate. In this mode, the rate of streaming is a half than setting and the size of
data block in a AMDTP packet is double than usual.

This commit add support for transmit stream (in stream) and fix some bugs...
bebob: add changing sampling frequency support for Focusrite devices

Accodrding to FFADO, to changing sampling rate, Saffire and Saffile LE
use Input/Output Plug Signal Format command but SaffirePro series use its own
register. And there are two registers to change sampling frequency. One
accompanies bus reset and another don't.

This commit support without bus reset.
fireworks/bebob: supplement Kconfig