perf test: test_intel_pt.sh: Print a message when skipping kernel tracing

Messages display with the perf test -v option. Add a message to show when
skipping a test because the user cannot do kernel tracing.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20221014170905.64069-4-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: ahunter6

tools/perf/tests/shell/test_intel_pt.sh

@@ -117,7 +117,14 @@ test_system_wide_side_band()
 
 can_kernel()
 {
-	perf_record_no_decode -o "${tmpfile}" -e dummy:k true >/dev/null 2>&1 || return 2
+	if [ -z "${can_kernel_trace}" ] ; then
+		can_kernel_trace=0
+		perf_record_no_decode -o "${tmpfile}" -e dummy:k true >/dev/null 2>&1 && can_kernel_trace=1
+	fi
+	if [ ${can_kernel_trace} -eq 0 ] ; then
+		echo "SKIP: no kernel tracing"
+		return 2
+	fi
 	return 0
 }