perf tools: Fix build failure on 32-bit arch

perf tools: Fix build failure on 32-bit arch

Failed in 32bit arch build like this:

    CC       /opt/h00206996/output/perf/arm32/builtin-record.o
  util/session.c: In function ‘perf_session__warn_about_errors’:
  util/session.c:1304:9: error: format ‘%lu’ expects argument of type ‘long unsigned int’,
                         but argument 2 has type ‘long long unsigned int’ [-Werror=format=]

  builtin-report.c: In function ‘perf_evlist__tty_browse_hists’:
  builtin-report.c:323:2: error: format ‘%lu’ expects argument of type ‘long unsigned int’,
                          but argument 3 has type ‘u64’ [-Werror=format=]

Replace %lu format strings in warning message with PRIu64 for u64
'total_lost_samples' to fix this problem.

Signed-off-by: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1434026664-71642-1-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>