perf tools: Add support for parsing PERF_SAMPLE_READ sample type

perf tools: Add support for parsing PERF_SAMPLE_READ sample type

Adding support to parse out the PERF_SAMPLE_READ sample bits.  The code
contains both single and group format specification.

This code parse out and prepare PERF_SAMPLE_READ data into the
perf_sample struct. It will be used for group leader sampling feature
comming in shortly.

Signed-off-by: Jiri Olsa <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Cc: Corey Ashford <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>