When we want to attach just to the thread that updates the display it
helps having its COMM stand out, so change it from the default "perf" to
"perf-top-UI".

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-5w0hmlk3zfvysxvpsh763k9w@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>