media: pulse8-cec: handle possible ping error

Handle (and warn about) possible error waiting for MSGCODE_PING result.

Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/cec/usb/pulse8/pulse8-cec.c

@@ -809,8 +809,11 @@ static void pulse8_ping_eeprom_work_handler(struct work_struct *work)
 
 	mutex_lock(&pulse8->lock);
 	cmd = MSGCODE_PING;
-	pulse8_send_and_wait(pulse8, &cmd, 1,
-			     MSGCODE_COMMAND_ACCEPTED, 0);
+	if (pulse8_send_and_wait(pulse8, &cmd, 1,
+				 MSGCODE_COMMAND_ACCEPTED, 0)) {
+		dev_warn(pulse8->dev, "failed to ping EEPROM\n");
+		goto unlock;
+	}
 
 	if (pulse8->vers < 2)
 		goto unlock;