perf tools: Add attr->mmap2 support

perf tools: Add attr->mmap2 support

This patch adds support for the new PERF_RECORD_MMAP2 record type
exposed by the kernel. This is an extended PERF_RECORD_MMAP record.

It adds for each file-backed mapping the device major, minor number and
the inode number and generation.

This triplet uniquely identifies the source of a file-backed mapping. It
can be used to detect identical virtual mappings between processes, for
instance.

The patch will prefer MMAP2 over MMAP.

Signed-off-by: Stephane Eranian <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ Cope with 314add6 "Change machine__findnew_thread() to set thread pid",
  fix 'perf test' regression test entry affected,
  use perf_missing_features.mmap2 to fallback to not using .mmap2 in older kernels,
  so that new tools can work with kernels where this feature is not present ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>