media: dvb-usb: fix wrong definition

syzbot reported WARNING in vmalloc. The problem
was in zero size passed to vmalloc.

The root case was in wrong cxusb_bluebird_lgz201_properties
definition. adapter array has only 1 entry, but num_adapters was
2.

Call Trace:
 __vmalloc_node mm/vmalloc.c:2963 [inline]
 vmalloc+0x67/0x80 mm/vmalloc.c:2996
 dvb_dmx_init+0xe4/0xb90 drivers/media/dvb-core/dvb_demux.c:1251
 dvb_usb_adapter_dvb_init+0x564/0x860 drivers/media/usb/dvb-usb/dvb-usb-dvb.c:184
 dvb_usb_adapter_init drivers/media/usb/dvb-usb/dvb-usb-init.c:86 [inline]
 dvb_usb_init drivers/media/usb/dvb-usb/dvb-usb-init.c:184 [inline]
 dvb_usb_device_init.cold+0xc94/0x146e drivers/media/usb/dvb-usb/dvb-usb-init.c:308
 cxusb_probe+0x159/0x5e0 drivers/media/usb/dvb-usb/cxusb.c:1634

Fixes: 4d43e13f72 ("V4L/DVB (4643): Multi-input patch for DVB-USB device")
Cc: stable@vger.kernel.org
Reported-by: syzbot+7336195c02c1bd2f64e1@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/usb/dvb-usb/cxusb.c

@@ -1947,7 +1947,7 @@ static struct dvb_usb_device_properties cxusb_bluebird_lgz201_properties = {
 
 	.size_of_priv     = sizeof(struct cxusb_state),
 
-	.num_adapters = 2,
+	.num_adapters = 1,
 	.adapter = {
 		{
 		.num_frontends = 1,