There is only one Asm streamer, there is no need for targets to register it.

There is only one Asm streamer, there is no need for targets to register it.

Instead, have the targets register a TargetStreamer to be use with the
asm streamer (if any).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232423 91177308-0d34-0410-b5e6-96231b3b80d8