_dev_ is being dereferenced before it is null checked, hence there
is a potential null pointer dereference.
Fix this by moving the pointer dereference after _dev_ has been null
checked.
Addresses-Coverity-ID: 
1462020
Fixes: bb1b40c7cb86 ("usbnet: ipheth: prevent TX queue timeouts when device not ready")
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 
 static int ipheth_carrier_set(struct ipheth_device *dev)
 {
-       struct usb_device *udev = dev->udev;
+       struct usb_device *udev;
        int retval;
+
        if (!dev)
                return 0;
        if (!dev->confirmed_pairing)
                return 0;
+
+       udev = dev->udev;
        retval = usb_control_msg(udev,
                        usb_rcvctrlpipe(udev, IPHETH_CTRL_ENDP),
                        IPHETH_CMD_CARRIER_CHECK, /* request */