[ROCm] Add HIP device synchronize event to profiler overhead filter (#4450)

Extend the profiler overhead filtering in benchmarks/float8/utils.py to ignore
hipDeviceSynchronize in addition to cudaDeviceSynchronize.
This keeps benchmark timing cleanup backend-agnostic for ROCm/HIP runs
and avoids counting device synchronization overhead as kernel time.

Signed-off-by: Jagadish Krishnamoorthy <jagadish.krishnamoorthy@amd.com>