media: dvb-usb: dw2102: fix uninit-value in su3000_read_mac_address

In su3000_read_mac_address, if i2c_transfer fails to execute two
messages, array mac address will not be initialized. Without handling
such error, later in function dvb_usb_adapter_dvb_init, proposed_mac
is accessed before initialization.

Fix this error by returning a negative value if message execution fails.

Link: https://lore.kernel.org/linux-media/20230328124416.560889-1-harperchen1110@gmail.comSigned-off-by: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

drivers/media/usb/dvb-usb/dw2102.c

@@ -946,7 +946,7 @@ static int su3000_read_mac_address(struct dvb_usb_device *d, u8 mac[6])
 	for (i = 0; i < 6; i++) {
 		obuf[1] = 0xf0 + i;
 		if (i2c_transfer(&d->i2c_adap, msg, 2) != 2)
-			break;
+			return -1;
 		else
 			mac[i] = ibuf[0];
 	}