perf tools: Replace mempcpy with memcpy

perf tools: Replace mempcpy with memcpy

mempcpy is not supported by bionic in Android and will lead to
compilation errors.

Replacing mempcpy with memcpy so it will work in Android.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/CANg8OW+Y3ZMG-GdhYu2_yKOYH_XEMgw73PdCX_23UTnfYhmttA@mail.gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>