perf tools: Add perf data cache feature

Storing CPU cache details under perf data. It's stored
as new HEADER_CACHE feature and it's displayed under
header info with -I option:

  $ perf report --header-only -I
  ...
  # CPU cache info:
  #  L1 Data                 32K [0-1]
  #  L1 Instruction          32K [0-1]
  #  L1 Data                 32K [2-3]
  #  L1 Instruction          32K [2-3]
  #  L2 Unified             256K [0-1]
  #  L2 Unified             256K [2-3]
  #  L3 Unified            4096K [0-3]
  ...

All distinct caches are stored/displayed.

Link: http://lkml.kernel.org/n/tip-byxl1gwto8z9d5hyozprtaty@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>