I am the code owner for Clang's IR generation; this has been true

I am the code owner for Clang's IR generation;  this has been true
for awhile, but it's good to make this official.

Just to be clear, Doug and Ted "elected" me to this position.

Might as well add myself to the credits list while I'm at it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136673 91177308-0d34-0410-b5e6-96231b3b80d8