perf evlist: Introduce perf_evlist__parse_sample

That is a more compact form of perf_session__parse_sample and to support
multiple evlists per perf_session is the way to go anyway.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-vkxx3j5qktoj11bvcwmfjj13@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>