perf kmem: Do not ignore mmap events

The perf kmem command didn't process mmap events for some unknown reason
and it instead gets symbol info from a running kernel.  This is
problematic if perf kmem record was run on a different kernel.

This patch adds the mmap event handlers and reverts the commit
e727ca73 ("perf kmem: Resolve kernel symbols again").

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1406872771-23933-1-git-send-email-namhyung@kernel.org


[ Fixed up merge conflict with Jiri's ordered_events rename patch set ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>