[Hexagon] Optimize argsort with vectorized Quicksort partition

[max-krasnyansky]

This PR optimizes the argsort operation in the Hexagon backend by vectorizing the Quicksort partition loop.

Changes:

1. ggml/src/ggml-hexagon/htp/hvx-base.h: Added hvx_vec_get_i32 helper function to extract a scalar integer from a vector, necessary for the reduction check.
2. ggml/src/ggml-hexagon/htp/argsort-ops.c:
   • Replaced quicksort_indices_asc and quicksort_indices_desc with quicksort_values_indices_asc and quicksort_values_indices_desc.
   • The new sorting functions sort the values scratchpad buffer directly and mirror the swaps to the indices buffer. This allows for contiguous vector loads from the values array, significantly speeding up the partition scan.
   • Implemented the partition scanning loop using HVX intrinsics (Q6_Q_vcmp_gt_VsfVsf).
   • Implemented a workaround for the missing Q6_Q_all_P instruction by using Q6_V_vmux_QVV to create a mask of 1s/0s and summing them with hvx_vec_reduce_sum_i32 to check if a whole block of 32 elements satisfies the pivot condition.
   • Updated htp_argsort_f32 to use the new sorting functions.

Performance:
The vectorized scan reduces the number of scalar comparisons and branch mispredictions during the partitioning phase of Quicksort, which is the most compute-intensive part of the operation.

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PR created automatically by Jules for task 9639307229427924630 started by @max-krasnyansky

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