PATCH: add pa2.0 system instructions

[Jerry Quinn]

>> "Jeff" == Jeffrey A Law <law@cygnus.com> writes:

[Brain death on opcodes snipped]

 Jeff> I've got a 95% functional PA2.0 assembler (and testsuite) that Cygnus
 Jeff> will be contributing to binutils after it's delivered to HP (June 30) &
 Jeff> cleaned up a little in July.  I don't know if that changes your plans
 Jeff> for contributing this kind of stuff.

I mostly started playing to get in the extra opcodes for long displacement
float load/store but started to look at completing the pa2.0 support.  So I
added the easy (!) stuff first.

If you have pa2.0 already working, I suppose it's silly for me to keep adding
the stuff to the current incarnation.  Is there anything that would make sense 
here for me to keep playing with?

Jerry