I munged the 5k/240 interrupt-enable and interrupt-handling
code to be closer to the XINE code.   I tested it and it works for me.
If anyone doesn't like it, please let me know.

I intend to redo some of the interrupt-enable code, such that
drivers can enable interrupts, rather than having CPU-model-specific
code deal with (almost) all the interrupts.  The newer code makes
this much easier.  Again, feedback on this, both positive and
negative, is solicited.

--Jonathan