perf intel-pt: Add reposition parameter to intel_pt_get_data()

When the decoder gets the next trace buffer, some state is reset if the
buffer is not consecutive to the previous buffer. Add a parameter
'reposition' so that can be done also to support a "fast forward"
facility.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190604130017.31207-8-adrian.hunter@intel.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>