perf tools: Fix SMT detection fast read path

sysfs__read_int() returns 0 on success, and so the fast read path was
always failing.

Fixes: bb62948 ("perf tools: Simplify checking if SMT is active.")
Signed-off-by: Ian Rogers <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: Kajol Jain <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Clarke <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: captain5050

tools/perf/util/smt.c

@@ -15,7 +15,7 @@ int smt_on(void)
 	if (cached)
 		return cached_result;
 
-	if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) > 0)
+	if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) >= 0)
 		goto done;
 
 	ncpu = sysconf(_SC_NPROCESSORS_CONF);