This is a resubmittal. For some reason it broke the bots yesterday

but I cannot reproduce the problem and have scrubed my sources and
even tested with llvm-lit -v --vg.

The Mips RDHWR (Read Hardware Register) instruction was not 
tested for assembler or dissassembler consumption. This patch
adds that functionality.

Contributer: Vladimir Medic
 
llvm-svn: 172685