SYCL: Add COUNT_EQUAL operator support

[yael-works]

Summary

This PR adds GGML_OP_COUNT_EQUAL support to the SYCL backend.

Changes

• Implemented ggml_sycl_op_count_equal() and its wrapper ggml_sycl_count_equal()
• Registered GGML_OP_COUNT_EQUAL in:
  • ggml_sycl_compute_forward()
  • ggml_backend_sycl_device_supports_op()
• Updated docs/ops.md and regenerated docs/ops/SYCL.csv to reflect SYCL support
• Added unit tests for COUNT_EQUAL:
  • Regular test case
  • Typed tests covering F32, F16, I32, and I16

Verification

• Built successfully with cmake + make
• Verified backend reports support:

  ./build/bin/test-backend-ops support -o COUNT_EQUAL -b sycl

[NeoZhangJianyu]

1. could you rebase the code since sycl_parallel_for() is reverted to stream->parallel_for() in base?
2. same commit of #15937.

Thank you!

[NeoZhangJianyu]

please remove duplicated code in this file.

[yael-works]

Thanks for the review!
I removed the duplicated op_count_equal definition from binbcast.hpp as requested.
The branch is now rebased on the latest master and clean.

[NeoZhangJianyu]

Thank you for great work!

[yael-works]

The iOS CI job is failing due to a missing SDK on the runner (iOS 26.0 is not installed), which seems unrelated to this PR.
All other CI checks have passed successfully.
This PR has already been reviewed and approved by @NeoZhangJianyu, and the requested changes from @slaren were addressed.
Could you please rerun the iOS job or proceed with merging if this failure is expected?