[mips][msa] Add DLSA instruction.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201081 91177308-0d34-0410-b5e6-96231b3b80d8
Test commit - added a new line to vec_shuf-insert.ll.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201083 91177308-0d34-0410-b5e6-96231b3b80d8