Quick fix for dragonegg about CreateAtomicCmpXchg, corresponding llvm r210903.

For now to follow r210903, simply extract i1 from ({i1,iN})Result.

git-svn-id: https://llvm.org/svn/llvm-project/dragonegg/trunk@210956 91177308-0d34-0410-b5e6-96231b3b80d8