[patch] change to MIPS 4650 instruction support

[Eric Christopher]

Daniel Jacobowitz wrote:

> > Do you mean within the assembler or the compiler?  I"m definitely
> > thinking of something similar for the compiler (look at the arm port for
> > examples), and am working on the infrastructure changes necessary to
> > support this.
> 
> I meant within the assembler, but the consensus seems to be that it's a
> bad idea.
> 

Yes.  I agree :)  Should probably just implement support for the
processor.  Far less work in the long run and it makes it easier to see
which processors are supported as opposed to seeing which processors fit
some combination of the available options :)

-eric