media: usb: Check az6007_read() return value

If az6007_read() returns error, there is no sence to continue.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 3af2f4f1 ("[media] az6007: Change the az6007 read/write routine parameter")
Signed-off-by: Daniil Dulov <d.dulov@aladdin.ru>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/usb/dvb-usb-v2/az6007.c

@@ -202,7 +202,8 @@ static int az6007_rc_query(struct dvb_usb_device *d)
 	unsigned code;
 	enum rc_proto proto;
 
-	az6007_read(d, AZ6007_READ_IR, 0, 0, st->data, 10);
+	if (az6007_read(d, AZ6007_READ_IR, 0, 0, st->data, 10) < 0)
+		return -EIO;
 
 	if (st->data[1] == 0x44)
 		return 0;