[mips] Set isAllocatable bit of unallocatable register classes to 0.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177128 91177308-0d34-0410-b5e6-96231b3b80d8
Remove some unused variables to clean the Clang -Werror build

(these were added in r177089)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177129 91177308-0d34-0410-b5e6-96231b3b80d8
Unaligned loads should use the VMOVUPS opcode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177130 91177308-0d34-0410-b5e6-96231b3b80d8