[mips][microMIPS] Implement ABS.fmt, CEIL.L.fmt, CEIL.W.fmt, FLOOR.L.fmt,...

[mips][microMIPS] Implement ABS.fmt, CEIL.L.fmt, CEIL.W.fmt, FLOOR.L.fmt, FLOOR.W.fmt, TRUNC.L.fmt, TRUNC.W.fmt, RSQRT.fmt and SQRT.fmt instructions
Differential Revision: http://reviews.llvm.org/D11674

llvm-svn: 246968