[ms-inline asm] Remove brackets from around a symbol reference in the target
specific logic.  This makes the code much less fragile.  Test case coming on the
clang side in a moment.
rdar://13634327


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179323 91177308-0d34-0410-b5e6-96231b3b80d8