perf tools: Add mem access sampling core support

This patch adds the sorting and histogram support
functions to enable profiling of memory accesses.

The following sorting orders are added:
 - symbol_daddr: data address symbol (or raw address)
 - dso_daddr: data address shared object
 - locked: access uses locked transaction
 - tlb : TLB access
 - mem : memory level of the access (L1, L2, L3, RAM, ...)
 - snoop: access snoop mode

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1359040242-8269-12-git-send-email-eranian@google.com


[ committer note: changed to cope with fc5871ed, the move of methods to
  machine.[ch], and the rename of dsrc to data_src, to match the change
  made in the PERF_SAMPLE_DSRC in a previous patch. ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>