perf tests: Compensate lower sample freq with longer test loop

Doesn't work for me:

./perf test -v 19
19: Test software clock events have valid period values :
--- start ---
mmap size 528384B
mmap size 528384B
All (0) samples have period value of 1!
---- end ----
Test software clock events have valid period values: FAILED!

Compensate the lower freq introduced in 67c1e4a53b17 with a longer loop,

Signed-off-by: Adrian Hunter <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Frederic Weisbecker <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mike Galbraith <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Paul Mackerras <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/tests/sw-clock.c

···
 #include "util/cpumap.h"
 #include "util/thread_map.h"
 
-#define NR_LOOPS  1000000
+#define NR_LOOPS  10000000
 
 /*
  * This test will open software clock events (cpu-clock, task-clock)