perf report: Use ui__warning in some more places

So that we get a proper warning in the TUI in cases like:

 $ perf report --stdio -g fractal,0.5,caller --sort pid
 Selected -g but no callchain data. Did you call 'perf record' without -g?
 $

The --stdio case is ok because it uses fprintf, ui__warning is needed to
figure out if --stdio or --tui is being used.

Cc: Arun Sharma <asharma@fb.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sam Liao <phyomh@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-ag9fz2wd17mbbfjsbznq1wms@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-report.c

@@ -162,23 +162,22 @@ static int perf_session__setup_sample_type(struct perf_session *self)
 {
 	if (!(self->sample_type & PERF_SAMPLE_CALLCHAIN)) {
 		if (sort__has_parent) {
-			fprintf(stderr, "selected --sort parent, but no"
-					" callchain data. Did you call"
-					" perf record without -g?\n");
+			ui__warning("Selected --sort parent, but no "
+				    "callchain data. Did you call "
+				    "'perf record' without -g?\n");
 			return -EINVAL;
 		}
 		if (symbol_conf.use_callchain) {
-			fprintf(stderr, "selected -g but no callchain data."
-					" Did you call perf record without"
-					" -g?\n");
+			ui__warning("Selected -g but no callchain data. Did "
+				    "you call 'perf record' without -g?\n");
 			return -1;
 		}
 	} else if (!dont_use_callchains && callchain_param.mode != CHAIN_NONE &&
 		   !symbol_conf.use_callchain) {
 			symbol_conf.use_callchain = true;
 			if (callchain_register_param(&callchain_param) < 0) {
-				fprintf(stderr, "Can't register callchain"
-						" params\n");
+				ui__warning("Can't register callchain "
+					    "params.\n");
 				return -EINVAL;
 			}
 	}