[Arm-netbook] SPDIF on EOMA68 A20

[luke.leighton]

> Modifying the specification at this point in the EOMA68 seems unlikely,

 not a chance.  audio was one of the first things that was eliminated
from putting out over the 68 pins due to there being no clear common
audio standard.  it is left to implementors to decide what ICs to
place on the I/O board, USB audio being the most sensible and
self-contained option.

l.