[hipSPARSELt] Remove legacy hip kernel launcher backend

[vin-huang]

Motivation

The spmm/hip/ directory contained a legacy standalone HIP kernel launcher
backend (KernelLauncher, KernelArguments, SolutionAdapter) that predates
the TensileLite integration. Since the build exclusively uses TensileLite
(BUILD_WITH_TENSILE is always defined), this code is dead and can be removed
to reduce maintenance burden and eliminate unused code paths.

Technical Details

Remove the spmm/hip/ folder and all associated files that implemented the
non-Tensile kernel dispatch path:

Files deleted:

• library/src/hcc_detail/rocsparselt/src/spmm/hip/hip_solution_adapter.cpp
• library/src/hcc_detail/rocsparselt/src/spmm/hip/kernel_arguments.cpp
• library/src/hcc_detail/rocsparselt/src/spmm/hip/kernel_launcher.cpp
• library/src/hcc_detail/rocsparselt/src/include/hip_solution_adapter.hpp
• library/src/hcc_detail/rocsparselt/src/include/kernel_arguments.hpp
• library/src/hcc_detail/rocsparselt/src/include/kernel_launcher.hpp

Files modified:

Simplified the #if BUILD_WITH_TENSILE / #else / #endif conditional include
blocks in the following files by removing the dead #else branches and
unconditionally including tensile_host.hpp:

• library/src/hcc_detail/rocsparselt/src/rocsparselt_auxiliary.cpp
• library/src/hcc_detail/rocsparselt/src/spmm/rocsparselt_spmm.hpp
• library/src/hcc_detail/rocsparselt/src/include/rocsparselt_spmm_utils.hpp

No CMakeLists.txt changes are required as the spmm/hip/ source files were
never listed in the build system.

Test Plan

• Build hipSPARSELt with TensileLite enabled (-DHIPSPARSELT_ENABLE_TENSILELITE=ON)
  and verify compilation succeeds with no missing header errors.
• Run existing hipSPARSELt unit tests (hipsparselt-test) to confirm no
  regressions in spmm/compress/prune functionality.

Test Result

• Build successful, no compilation errors.
• All existing spmm unit tests pass.

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

https://amd-hub.atlassian.net/browse/ROCM-26968