[mips] Add assembler support for .set msa/nomsa directive.

Summary:
These directives are used to toggle whether the assembler accepts MSA-specific instructions or not.

Patch by Matheus Almeida and Toma Tabacu.

Reviewers: dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D4783


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215099 91177308-0d34-0410-b5e6-96231b3b80d8
Silencing an MSVC C4334 warning ('<<' : result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?)). No functional changes intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215100 91177308-0d34-0410-b5e6-96231b3b80d8
Insert parens to avoid a warning:
  suggest parentheses around arithmetic in operand of '^' [-Wparentheses]


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215101 91177308-0d34-0410-b5e6-96231b3b80d8
Add first bunch of SPE instructions. As they overlap with Altivec, mark
them as parser-only until the disassembler is extended to handle
predicates properly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215102 91177308-0d34-0410-b5e6-96231b3b80d8
Spell e500 feature in lower case.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215103 91177308-0d34-0410-b5e6-96231b3b80d8
Fix Itineray class of rfi

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215104 91177308-0d34-0410-b5e6-96231b3b80d8
Add RFID instruction.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215105 91177308-0d34-0410-b5e6-96231b3b80d8