feat: Add SYCL kernels for Q1_0 and Q1_0_g128 quantization types (Intel Arc / oneAPI)

[vrwallace]

Summary

Adds SYCL/oneAPI compute kernels for the Q1_0 and Q1_0_g128 quantization
types used by PrismML Bonsai 8B models, enabling full GPU offload on Intel Arc
GPUs via the Intel oneAPI Level Zero backend.

Without this patch:

fatal error: unsupport data type=q1_0_g128
Aborted

With this patch, all 37 model layers offload to the GPU and inference runs at
~43-46 tok/s on an Intel Arc Pro B50 (BMG G21).

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Changes

ggml/src/ggml-sycl/vecdotq.hpp

• Added vec_dot_q1_0_q8_1 — dot product for Q1_0 (32-weight blocks)
• Added vec_dot_q1_0_g128_q8_1 — dot product for Q1_0_g128 (128-weight blocks)
• Ported from PrismML CUDA kernels in ggml-cuda/vecdotq.cuh
• bit=1 → +d, bit=0 → -d; Q8_1 scale factor applied correctly per block

ggml/src/ggml-sycl/mmvq.cpp

• Added mul_mat_vec_q1_0_q8_1_sycl dispatch function
• Added mul_mat_vec_q1_0_g128_q8_1_sycl dispatch function
• Added GGML_TYPE_Q1_0 and GGML_TYPE_Q1_0_g128 cases to the switch in
  ggml_sycl_op_mul_mat_vec_q

ggml/src/ggml-sycl/convert.cpp

• Added dequantize_row_q1_0_sycl
• Added dequantize_row_q1_0_g128_sycl
• Added cases to both ggml_get_to_fp16_sycl and ggml_get_to_fp32_sycl

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Test Hardware

• GPU: Intel Arc Pro B50 (BMG G21, Battlemage)
• Driver: Mesa ANV 25.2.8 / Intel oneAPI Level Zero
• OS: Ubuntu Noble 24.04, kernel 6.17

Test Model

• prism-ml/Bonsai-8B-gguf (Q1_0_g128, 1.08 GB)

Results

load_tensors:   CPU_Mapped  =    83.31 MiB  (non-quantized tensors only)
load_tensors:   SYCL0       =  1015.99 MiB  (all Q1_0_g128 layers on GPU)
offloaded 37/37 layers to GPU

prompt:     ~55 tok/s
generation: ~46 tok/s

Notes

• Vulkan backend does NOT work for Q1_0_g128 on Intel Arc — Mesa ANV for
  Battlemage lacks VK_KHR_shader_integer_dot_product. SYCL is currently
  the only working GPU path on Arc for Bonsai models.
• --reasoning off is required to suppress the embedded Qwen3 thinking
  template in Bonsai GGUFs.

[vrwallace]

@timothycarambat happy to discuss any changes needed