perf test: Fix skipping branch stack sampling test

Commit f4a2aade6809c657 ("perf tests powerpc: Fix branch stack sampling
test to include sanity check for branch filter") added a skip if certain
branch options aren't available.

But the change added both -b (--branch-any) and --branch-filter options
at the same time, which will always result in a failure on any platform
because the arguments can't be used together.

Fix this by removing -b (--branch-any) and leaving --branch-filter which
already specifies 'any'. Also add warning messages to the test and perf
tool.

Output on x86 before this fix:

$ sudo ./perf test branch
108: Check branch stack sampling : Skip

After:

$ sudo ./perf test branch
108: Check branch stack sampling : Ok

Fixes: f4a2aade6809c657 ("perf tests powerpc: Fix branch stack sampling test to include sanity check for branch filter")
Signed-off-by: James Clark <[e-mail]>
Tested-by: Athira Jajeev <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: [e-mail]
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/tests/shell/test_brstack.sh

···
 
 # skip the test if the hardware doesn't support branch stack sampling
 # and if the architecture doesn't support filter types: any,save_type,u
-perf record -b -o- -B --branch-filter any,save_type,u true > /dev/null 2>&1 || exit 2
+if ! perf record -o- --no-buildid --branch-filter any,save_type,u -- true > /dev/null 2>&1 ; then
+	echo "skip: system doesn't support filter types: any,save_type,u"
+	exit 2
+fi
 
 TMPDIR=$(mktemp -d /tmp/__perf_test.program.XXXXX)
 

tools/perf/util/parse-branch-options.c

···
 	/*
 	 * cannot set it twice, -b + --branch-filter for instance
 	 */
-	if (*mode)
+	if (*mode) {
+		pr_err("Error: Can't use --branch-any (-b) with --branch-filter (-j).\n");
 		return -1;
+	}
 
 	return parse_branch_str(str, mode);
 }