perf/record: simplify TRACE_INFO tracepoint check

Fix a couple of inefficiencies and redundancies related to
have_tracepoints() and its use when checking whether to write
TRACE_INFO.

First, there's no need to use get_tracepoints_path() in
have_tracepoints() - we really just want the part that checks whether
any attributes correspondo to tracepoints.

Second, we really don't care about raw_samples per se - tracepoints
are always raw_samples.  In any case, the have_tracepoints() check
should be sufficient to decide whether or not to write TRACE_INFO.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>,
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1273030770.6383.6.camel@tropicana>
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>