perf tools: Skip BPF sideband event for userspace profiling

perf tools: Skip BPF sideband event for userspace profiling

The BPF sideband information is tracked using a separate thread and
evlist.  But it's only useful for profiling kernel and we can skip it
when users profile their application only.

It seems it already fails to open the sideband event in that case.
Let's remove the noise in the verbose output anyway.

Reviewed-by: Ian Rogers <irogers@google.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20250226203039.1099131-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>