llvm2.9: allow parallel native make

* fix parallel build
  Doing a parallel build may result in the following:
  *** No rule to make target `native/bin/tblgen', needed by `include/llvm/Intrinsics.gen.tmp'
  Avoid this by building tblgen first before building the rest of llvm.

Signed-off-by: Jonathan Liu <net147@gmail.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>