ci: add LoongArch cross-compile build (ggml-org#13944)

fixes ggml-org#7999 (adds control vectors to all `build_XXX()` functi…

…ons in `llama.cpp` [needs testing] (ggml-org#8060)

* fixes ggml-org#7999

The `build_command_r` forgot to add the control vector.

* Fixes qwen2 too

* Fixed all models' control vectors

* Removed double calls to `cb(cur, "l_out", il)`

* Moved control vector logic to llama_control_vector:apply_to()