Fix segmentation fault in NLLLoss kernel

[yucai-intel]

Fixed the following issues found by test/test_nn.py::TestNNDeviceTypeXPU::test_nll_loss_large_tensor_reduction_mean_xpu and test_nll_loss_large_tensor_reduction_sum_xpu

1. Segmentation faults caused by pointer type conversion errors that result in invalid memory addresses.
2. Kernel call errors caused by incorrect judgment conditions.

[yucai-intel]

issue link #2008

[yucai-intel]

[Copilot]

Pull Request Overview

This PR fixes segmentation faults and kernel call errors in the NLLLoss kernel implementation for XPU devices. The changes refactor the kernel functors to use safer memory access patterns and more consistent parameter ordering.

Key changes include:

• Complete rewrite of kernel functors with improved memory safety and bounds checking
• Simplified function signatures with reordered parameters for better consistency
• Addition of proper index validation and overflow protection

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
src/ATen/native/xpu/sycl/LossNLLKernel.h	Updated function signatures to reorder parameters and use consistent naming
src/ATen/native/xpu/sycl/LossNLLKernel.cpp	Major refactor of kernel implementations with improved memory safety and bounds checking
src/ATen/native/xpu/sycl/KernelUtils.h	Added utility constants and functions for kernel execution
src/ATen/native/xpu/LossNLL.cpp	Updated function calls to match new kernel signatures

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[yucai-intel]

Pref

[guangyey]

LGTM.

[CuiYifeng]

The main part of this PR looks good to me.