perf trace: Remove needless reassignments

The thread->priv value is already obtained a few lines earlier from the
thread__trace() call. Leftovers from before thread__trace().

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-96laa634vzfwlwxurevo40wp@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -1629,7 +1629,6 @@ static int trace__sys_enter(struct trace *trace, struct perf_evsel *evsel,
 		return -1;
 
 	args = perf_evsel__sc_tp_ptr(evsel, args, sample);
-	ttrace = thread->priv;
 
 	if (ttrace->entry_str == NULL) {
 		ttrace->entry_str = malloc(1024);
@@ -1687,8 +1686,6 @@ static int trace__sys_exit(struct trace *trace, struct perf_evsel *evsel,
 		++trace->stats.vfs_getname;
 	}
 
-	ttrace = thread->priv;
-
 	ttrace->exit_time = sample->time;
 
 	if (ttrace->entry_time) {