The previous prep patch was just to show exactly what changed in that
function, now its time to move that method and things only it uses to
the right place, mmap.[ch]

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-aaxywfgw3d44x6xlu8zm1avu@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>