perf tools: Add a per tracepoint counter attribute to get raw sample

Add a new flag field while opening a tracepoint perf counter:

	-e tracepoint_subsystem:tracepoint_name:flags

This is intended to be generic although for now it only supports the
r[e[c[o[r[d]]]]] flag:

	./perf record -e workqueue:workqueue_insertion:record
	./perf record -e workqueue:workqueue_insertion:r

will have the same effect: enabling the raw samples record for
the given tracepoint counter.

In the future, we may want to support further flags, separated
by commas.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1250152039-7284-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>