Remove the deprecated gpu_id.

[trivialfis]

No description provided.

[Copilot]

Pull Request Overview

This PR removes support for the deprecated gpu_id parameter in favor of using the device parameter consistently. Key changes include:

• Updating tests to remove usage of gpu_id in favor of device.
• Removing gpu_id from learner configuration and its backward compatibility handling.
• Changing the handling of deprecated gpu_id in context and error reporting, as well as removing gpu_id in the Spark interface.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/cpp/gbm/test_gbtree.cc	Updated test cases to use device instead of gpu_id.
src/learner.cc	Removed gpu_id from the list of configuration keys.
src/context.cc	Adjusted gpu_id handling to only warn via WarnDeprecatedGPUId.
src/common/error_msg.cc	Changed the log level for deprecated gpu_id from WARNING to FATAL.
python-package/xgboost/spark/core.py	Removed gpu_id from unsupported parameters.

Comments suppressed due to low confidence (2)

src/context.cc:247

• Deprecated 'gpu_id' is now only warned via WarnDeprecatedGPUId and processing continues. If removal is intended, consider returning immediately or explicitly handling the absence of device to avoid unintended behavior when only gpu_id is provided.

  if (has_gpu_id) {

src/common/error_msg.cc:45

• Changing the log level from WARNING to FATAL in WarnDeprecatedGPUId now terminates execution on deprecated usage. Verify that this breaking change is intended and that downstream tests and user expectations have been updated accordingly.

    LOG(FATAL) << msg;