R600/SI: Match ctlz_zero_undef

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211115 91177308-0d34-0410-b5e6-96231b3b80d8
R600/SI: Match cttz_zero_undef

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211116 91177308-0d34-0410-b5e6-96231b3b80d8