[MVT] add v1i1 MVT

Adds the v1i1 MVT as a preparation for another commit (https://reviews.llvm.org/D32273)

Differential Revision: https://reviews.llvm.org/D32540

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303346 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed