[committed] Make MIPS VR5400 opcodes more like MDMX

[Maciej W. Rozycki]

On Mon, 8 Jul 2013, Richard Sandiford wrote:

> I was reading the same manual (version 5).

 Mine is also version 5 and I am blind.  Sorry to cause you the confusion.  
Their choice of MDMX limitations to make seems weird.

> The "P" operand type, used for MFPC, MTPC, etc.

 OK, thanks, I thought you meant something related to the MDMX ASE.

  Maciej