[mips][microMIPS] Implement ADD.fmt, SUB.fmt, MOV.fmt, MUL.fmt, DIV.fmt,...

[mips][microMIPS] Implement ADD.fmt, SUB.fmt, MOV.fmt, MUL.fmt, DIV.fmt, MADDF.fmt, MSUBF.fmt and NEG.fmt instructions
Differential Revision: http://reviews.llvm.org/D11978

llvm-svn: 246919