Adding MEM_TOPOLOGY feature to perf data file,
that will carry physical memory map and its
node assignments.

The format of data in MEM_TOPOLOGY is as follows:

  0 - version          | for future changes
  8 - block_size_bytes | /sys/devices/system/memory/block_size_bytes
 16 - count            | number of nodes

 For each node we store map of physical indexes for
 each node:

 32 - node id          | node index
 40 - size             | size of bitmap
 48 - bitmap           | bitmap of memory indexes that belongs to node
                       | /sys/devices/system/node/node<NODE>/memory<INDEX>

The MEM_TOPOLOGY could be displayed with following
report command:

  $ perf report --header-only -I
  ...
  # memory nodes (nr 1, block size 0x8000000):
  #    0 [7G]: 0-23,32-69
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180307155020.32613-8-jolsa@kernel.org
[ Rename 'index' to 'idx', as this breaks the build in rhel5, 6 and other systems where this is used by glibc headers ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>