perf tools: Fix include of linux/mman.h

It was using uapi/linux/mmap.h which caused for at least one reporter,
that hasn't specified in what environment the problem manifests itself:

 ----
The original error is:

In file included from util/event.c:2:0:
...tools/include/uapi/linux/mman.h:4:27: fatal error: uapi/asm/mman.h:
No such file or directory
 #include <uapi/asm/mman.h>
                           ^
compilation terminated.
 ----

Test built it on these containers:

  # dm
   1 alpine:3.4: Ok
   2 android-ndk:r12b-arm: Ok
   3 archlinux:latest: Ok
   4 centos:5: Ok
   5 centos:6: Ok
   6 centos:7: Ok
   7 debian:7: Ok
   8 debian:8: Ok
   9 debian:experimental: Ok
  10 debian:experimental-x-arm64: Ok
  11 debian:experimental-x-mips: Ok
  12 debian:experimental-x-mips64: Ok
  13 debian:experimental-x-mipsel: Ok
  14 fedora:20: Ok
  15 fedora:21: Ok
  16 fedora:22: Ok
  17 fedora:23: Ok
  18 fedora:24: Ok
  19 fedora:24-x-ARC-uClibc: Ok
  20 fedora:25: Ok
  21 fedora:rawhide: Ok
  22 mageia:5: Ok
  23 opensuse:13.2: Ok
  24 opensuse:42.1: Ok
  25 opensuse:tumbleweed: Ok
  26 ubuntu:12.04.5: Ok
  27 ubuntu:14.04.4-x-linaro-arm64: Ok
  28 ubuntu:15.10: Ok
  29 ubuntu:16.04: Ok
  30 ubuntu:16.04-x-arm: Ok
  31 ubuntu:16.04-x-arm64: Ok
  32 ubuntu:16.04-x-powerpc: Ok
  33 ubuntu:16.04-x-powerpc64: Ok
  34 ubuntu:16.04-x-powerpc64el: Ok
  35 ubuntu:16.04-x-s390: Ok
  36 ubuntu:16.10: Ok
Reported-by: David Carrillo-Cisneros <davidcc@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: fbef103f ("perf tools: Do hugetlb handling in more systems")
Link: http://lkml.kernel.org/n/tip-4wm5xmjz5wgbq7ucyz4dyd72@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/event.c

 #include <linux/types.h>
-#include <uapi/linux/mman.h> /* To get things like MAP_HUGETLB even on older libc headers */
+#include <linux/mman.h> /* To get things like MAP_HUGETLB even on older libc headers */
 #include <api/fs/fs.h>
 #include "event.h"
 #include "debug.h"