perf annotate TUI: Fix --show-total-period

We were showing the number of samples, not the total period, fix it.

Reported-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Martin Liška <mliska@suse.cz>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Fixes: 0c4a5bce ("perf annotate: Display total number of samples with --show-total-period")
Link: http://lkml.kernel.org/r/1500500223-16753-1-git-send-email-treeze.taeung@gmail.com


[ extracted from a larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>