perf test: Improve verbose documentation

JIRA: https://issues.redhat.com/browse/RHEL-77936

upstream
========
commit 4e38f28
Author: Ian Rogers <irogers@google.com>
Date: Thu Jan 9 20:57:36 2025 -0800

description
===========
Add a little more detail on the output expectations for each verbose
level.

    Signed-off-by: Ian Rogers <irogers@google.com>
    Reviewed-by: Namhyung Kim <namhyung@kernel.org>
    Cc: James Clark <james.clark@linaro.org>
    Link: https://lore.kernel.org/r/20250110045736.598281-6-irogers@google.com
    Signed-off-by: Namhyung Kim <namhyung@kernel.org>

Signed-off-by: Michael Petlan <mpetlan@redhat.com>

Author: rfmvh

tools/perf/Documentation/perf-test.txt

@@ -28,8 +28,11 @@ OPTIONS
 	Tests to skip (comma separated numeric list).
 
 -v::
+-vv::
+-vvv::
 --verbose::
-	Be more verbose.
+	With a single '-v', verbose level 1, only failing test output
+	is displayed. With '-vv' and higher all test output is shown.
 
 -S::
 --sequential::