[media] dib0700: fix possible NULL pointer dereference

Seems like 'adap->fe' test for NULL was meant to be before we dereference
that pointer.
Signed-off-by: Mariusz Kozlowski <mk@lab.zgora.pl>
Signed-off-by: Patrick Boettcher <pboettcher@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/dvb-usb/dib0700_devices.c

@@ -2440,11 +2440,11 @@ static int tfe7090pvr_frontend0_attach(struct dvb_usb_adapter *adap)
 	dib0700_set_i2c_speed(adap->dev, 340);
 	adap->fe = dvb_attach(dib7000p_attach, &adap->dev->i2c_adap, 0x90, &tfe7090pvr_dib7000p_config[0]);
 
-	dib7090_slave_reset(adap->fe);
-
 	if (adap->fe == NULL)
 		return -ENODEV;
 
+	dib7090_slave_reset(adap->fe);
+
 	return 0;
 }