[CMake] llvm-ar depends on intrinsics_gen

llvm-ar.cpp has the following include chain:

llvm/IR/Module.h
llvm/IR/Function.h
llvm/IR/Argument.h
llvm/IR/Attributes.h
llvm/IR/Attributes.gen

This means llvm-ar needs to depend on intrinsics_gen.

llvm-svn: 287395