Include IR/DerivedTypes.h instead of IR/Type.h to match LLVM change r256406.

This is similar to r256407 and fixes the following warning:

In file included from /work/llvm-3.8/llvm.src/tools/lldb/source/Target/ThreadPlanCallFunctionUsingABI.cpp:14:
In file included from /work/llvm-3.8/llvm.src/tools/lldb/include/lldb/Target/ThreadPlanCallFunctionUsingABI.h:23:
/work/llvm-3.8/llvm.src/include/llvm/IR/Type.h:350:16: error: inline function 'llvm::Type::getSequentialElementType' is not defined [-Werror,-Wundefined-inline]
  inline Type *getSequentialElementType() const;
               ^
/work/llvm-3.8/llvm.src/include/llvm/IR/Type.h:353:46: note: used here
  Type *getArrayElementType() const { return getSequentialElementType(); }
                                             ^
1 error generated.

I'm not sure why it's not showing on any bots.

llvm-svn: 257691