refactor(device): remove dead code from DeviceContext, add dsp_count guard

[Cstandardlib]

Summary

Removes dead code from DeviceContext and adds a dsp_count > 0 guard to prevent modulo-by-zero.

Changes

1. Remove dead device_type subsystem from DeviceContext (device.h)

Exhaustive code search across entire source/ tree confirmed zero callers for:

Removed	Lines	Reason
set_device_type()	1	Zero callers
get_device_type() member	1	Never called directly; all 48 get_device_type() call sites use the template version from device_helpers.h
is_cpu()	1	Zero callers
is_gpu()	1	Zero callers (3 occurrences of is_gpu in codebase are local bool variables, not this method)
is_dsp()	1	Zero callers
is_initialized()	1	Zero callers
is_gpu_enabled()	1	Zero callers

Also removed:

• Standalone get_device_type(const DeviceContext*) — zero callers (all call sites use get_device_type(const Device*) template)
• Forward declaration in device_helpers.h

Kept (all have active callers): init(), get_device_id(), get_device_count(), get_local_rank()

2. Add dsp_count > 0 guard (driver.cpp)

#ifdef __DSP
    assert(PARAM.inp.dsp_count > 0);
    // ... existing set_dsp_cluster_id calls
#endif

Prevents modulo-by-zero undefined behavior (4 sites do MY_RANK % dsp_count; dsp_count defaults to 4 but has no input validation).

[Copilot]

Pull request overview

This PR is a cleanup/refactor following the DSP routing fix work, removing unused DeviceContext “device_type” APIs and adding a guard intended to prevent modulo-by-zero when computing DSP cluster IDs from dsp_count.

Changes:

• Removed the unused DeviceContext runtime device_type accessors and the associated device_type_ field.
• Removed the unused get_device_type(const DeviceContext*) runtime helper declaration.
• Added a dsp_count > 0 guard before computing DSP cluster IDs in Driver::reading().

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
source/source_main/driver.cpp	Adds a DSP dsp_count guard before setting DSP cluster IDs for memory/BLAS routing.
source/source_base/module_device/device.h	Removes unused DeviceContext runtime device-type APIs and device_type_ storage.
source/source_base/module_device/device_helpers.h	Removes unused runtime get_device_type(const DeviceContext*) forward declaration.

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