media: dvb_frontend: don't call dvb_frontend_get_stepsize() twice

Avoid calling the function twice, as it was just called at the
previous line.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/dvb-core/dvb_frontend.c

@@ -1821,7 +1821,7 @@ static void prepare_tuning_algo_parameters(struct dvb_frontend *fe)
 		case SYS_DTMB:
 			fepriv->min_delay = HZ / 20;
 			fepriv->step_size = dvb_frontend_get_stepsize(fe) * 2;
-			fepriv->max_drift = (dvb_frontend_get_stepsize(fe) * 2) + 1;
+			fepriv->max_drift = fepriv->step_size + 1;
 			break;
 		default:
 			/*