add CI_VISIBLE_DEVICES env variable to distinguish between CI

execution in parallel vs serial run by hand

Signed-off-by: Karl W Schulz <karl.schulz@amd.com>

.github/workflows/mi-rhel9.yml

@@ -28,6 +28,7 @@ jobs:
 
     env:
        PYTHONPATH: /home1/ciuser/omniperf_deps
+       CI_VISIBLE_DEVICES 1
     name: ROCm v${{ matrix.version }} / ${{ matrix.hardware }}
     steps:
       - name: Checkout