[testlib] Fix ROCm build

[cedricjourdain]

This PR addresses minor build and type consistency issues in gpu microbenchmarksrelated these are related to the "new" hierarchy of ROCm folder:

• Added -I${ROCM_ROOT}/include/rocblas/ in HIP Makefiles to ensure rocblas.h is properly found.
• Linked with -lpthread to prevent potential linkage errors.
• Defined ROCM_ROOT?=/opt/rocm/ for consistent default paths across builds.
• Fixed numa_node type in smi.hpp from uint32_t to int32_t to match rsmi_topo_numa_affinity_get() API expectations.

Compilation validated with ROCm 6.x on MI250 AMD GPUs

[vkarak]

Lgtm

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.25%. Comparing base (a71c68b) to head (b663a61).
⚠️ Report is 2 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3574      +/-   ##
===========================================
- Coverage    91.26%   91.25%   -0.02%     
===========================================
  Files           62       62              
  Lines        13534    13534              
===========================================
- Hits         12352    12350       -2     
- Misses        1182     1184       +2     

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