The command line like 'perf report --stdio --time 1abc%/1' could be
accepted by perf. It looks not very good.

This patch uses strtod() to replace original atof() and check the entire
string. Now for the same command line, it would return error message
"Invalid time string".

root@skl:/tmp# perf report --stdio --time 1abc%/1
Invalid time string
Signed-off-by: NJin Yao <yao.jin@linux.intel.com>
Reviewed-by: NJiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1515596433-24653-4-git-send-email-yao.jin@linux.intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>