AMDGPU: Fix incorrectly setting kill flag when copying register tuples

This fixes some verifier errors when trackLivenessAfterRegAlloc is
enabled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271446 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed