ggml : update `ggml_rope_multi` (ggml-org#12665)

* update `rope_multi`:

1. add `ggml_rope_multi_inplace`;
1. use `GGML_MROPE_SECTIONS` instead of 4.

* Apply suggestions from code review

Co-authored-by: Georgi Gerganov <[email protected]>

---------

Co-authored-by: Georgi Gerganov <[email protected]>