perf top: Fix --delay_secs 0 division by zero

Add delay_secs sanity check to handle_keypress,
this fixes a division by zero crash.

Signed-off-by: Tim Blechmann <tim@klingt.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4AD9EBFD.106@klingt.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-top.c

@@ -686,6 +686,8 @@ static void handle_keypress(int c)
 	switch (c) {
 		case 'd':
 			prompt_integer(&delay_secs, "Enter display delay");
+			if (delay_secs < 1)
+				delay_secs = 1;
 			break;
 		case 'e':
 			prompt_integer(&print_entries, "Enter display entries (lines)");