Joakim reported wrong duration_time value for interval bigger
than 4000 [1].

The problem is in the interval value we pass to update_stats
function, which is typed as 'unsigned int' and overflows when
we get over 2^32 (happens between intervals 4000 and 5000).

Retyping the passed value to unsigned long long.

[1] https://www.spinics.net/lists/linux-perf-users/msg11777.html

Fixes: b90f1333 ("perf stat: Update walltime_nsecs_stats in interval mode")
Reported-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200518131445.3745083-1-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>