perf powerpc: Add basic CONFIG_AUXTRACE support for VPA pmu on powerpc

perf powerpc: Add basic CONFIG_AUXTRACE support for VPA pmu on powerpc

The powerpc PMU collecting Dispatch Trace Log (DTL) entries makes use of
AUX support in perf infrastructure.

The PMU driver has the functionality to collect trace entries in the aux
buffer.

On the tools side, this data is made available as PERF_RECORD_AUXTRACE
records.

This record is generated by "perf record" command.

To enable the creation of PERF_RECORD_AUXTRACE, add functions to
initialize auxtrace records ie "auxtrace_record__init()".

Fill in fields for other callbacks like info_priv_size, info_fill, free,
recording options etc.

Define auxtrace_type as PERF_AUXTRACE_VPA_DTL.  Add header file to
define vpa dtl pmu specific details.

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.ibm.com>
Tested-by: Tejas Manhas <tejas05@linux.ibm.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Aboorva Devarajan <aboorvad@linux.ibm.com>
Cc: Aditya Bodkhe <Aditya.Bodkhe1@ibm.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>