MFC: (revision 1.47, 1.48)

MFC: (revision 1.47, 1.48)

- Add missing MCP65 id which was accidentally removed in previous commit.
- Add Analog Devices AD1984 codec id.
- Enable pcbeep control for Acer + ALC268 (nid 29). Give enough (fake)
  hints so the parser will grab it and allocate "speaker" control.
- Fix regression while preparing DAC and ADC for multichannel
  format. Since playback policy is to output to every possible path,
  ensure that each DAC is started.

Reported / Tested by:	Guy Brand
Approved by:		re (kensmith)