perf tools: Replace error() with pr_err()

To consolidate the error reporting facility.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-b41iot1094katoffdf19w9zk@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 39996c5..322b4de 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -2066,7 +2066,7 @@
 	if (thread__resolve_callchain(thread, cursor, evsel, sample,
 				      NULL, NULL, sched->max_stack + 2) != 0) {
 		if (verbose > 0)
-			error("Failed to resolve callchain. Skipping\n");
+			pr_err("Failed to resolve callchain. Skipping\n");
 
 		return;
 	}