[mips][microMIPS] Implement AND16, NOT16, OR16 and XOR16 instructions
Differential Revision: http://reviews.llvm.org/D5117


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220275 91177308-0d34-0410-b5e6-96231b3b80d8