[MSSA] Clean up the updater a bit. NFC

- Mark an internal function static
- Remove the llvm namespace (just holding on to the `using namespace
  llvm;` Works on My Machine(TM))


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300947 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed