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>

ggml/src/ggml-hexagon/htp/htp-ops.h

@@ -83,6 +83,8 @@ enum htp_op_code {
     HTP_OP_FILL,
     HTP_OP_DIAG,
     HTP_OP_SOLVE_TRI,
+    HTP_OP_L2_NORM,
+
     HTP_OP_INVALID
 };