www: update lldb architecture doc
www: update lldb architecture doc

ArchSpec was moved from Core to Utility, so I modified the docs to
reflect that.

Patch by Alex Langford <apl@fb.com>!

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@323363 91177308-0d34-0410-b5e6-96231b3b80d8

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