V4L/DVB (7731): tuner-xc2028: fix signal strength calculus

	/* Sync Lock Indicator */

	rc = xc2028_get_reg(priv, 0x0002, &frq_lock);

	if (rc < 0 || frq_lock == 0)

	if (rc < 0)

		goto ret;

	/* Frequency is locked. Return signal quality */

	/* Frequency is locked */

	if (frq_lock == 1)

		signal = 32768;

	/* Get SNR of the video signal */

	rc = xc2028_get_reg(priv, 0x0040, &signal);

	if (rc < 0)

		signal = -frq_lock;

		goto ret;

	/* Use both frq_lock and signal to generate the result */

	signal = signal || ((signal & 0x07) << 12);

ret:

	mutex_unlock(&priv->lock);

	*strength = signal;

	tuner_dbg("signal strength is %d\n", signal);

	return rc;

}