Make GetCPISymbol a virtual method.

ARM64 for iOS is going to want to emit these symbols in a
linker-private style for efficiency, but other targets probably don't
want that behaviour.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205080 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed