perf test: Don't fail if user rdpmc returns 0 when disabled

In certain hypervisor set ups the value 0 may be returned but this is
only erroneous if the user rdpmc isn't disabled.

Signed-off-by: Ian Rogers <[e-mail]>
Signed-off-by: Namhyung Kim <[e-mail]>

tools/perf/tests/mmap-basic.c

···
 		}
 
 		perf_evsel__read(evsel, 0, 0, &counts);
-		if (counts.val == 0) {
+		if (rdpmc_supported && counts.val == 0) {
 			pr_err("User space counter reading for PMU %s [Failed read]\n", pmu->name);
 			ret = TEST_FAIL;
 			goto cleanup;