perf tools: Convert open coded equivalents to asprintf()

The following snippet
	V = malloc(S);
	if (!V) { }
	sprintf(V, ...)

Can be easily changed to a one line:

	if (asprintf(&V, ...) < 0) { }

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Link: http://lkml.kernel.org/r/1404474229-15272-1-git-send-email-andriy.shevchenko@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --cc tools/perf/util/trace-event-info.c
Simple merge

diff --cc tools/perf/util/util.c
Simple merge