Fix build break on Ubuntu 12.04 with ARM64 changes.
Fix build break on Ubuntu 12.04 with ARM64 changes.

See http://llvm.org/bugs/show_bug.cgi?id=20824 for more details.

Tested:
Ubuntu 12.04 x86_64, gcc-4.9.1-built lldb
Ubuntu 14.04 x86_64, clang-3.5-build lldb



git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@217169 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb