Making this change is not as trivial as it seems, because the
am79900 structures take a short-cut of munging together fields.  The chip
actually byte-swaps individual fields, so the device driver needs to
separate out more fields.  I have done this and I am going to test it
soon. 

	The driver also has a potential problem that the descriptors are
defined in a shadow structure and then copied to the real descriptors seen
by the chip, but that only is correct if the copy is atomic -- which it is
not.  The status bits are in the middle of the descriptor structure, so
the "ownership" bit could flip without the descriptor in a completely
self-consitent start.  If some asynchronous event caused the chip to start
before the explicit CSR kick, things could go wrong.

David