Feature hexagon l2 norm (#22816)
* L2_NORM Updates
* Addressed PR Comments
* ggml-hexagon: add L2_NORM HVX kernel for Hexagon backend
* hex-unary: remove supported_unary_nc since the outer loop is the same for all unary ops
---------
Co-authored-by: Max Krasnyansky <maxk@qti.qualcomm.com>
