[media] si2157: Add support for delivery system SYS_ATSC

Set the property for delivery system also in case of SYS_ATSC. This
behaviour is observed in the sniffs taken with Hauppauge HVR-955Q
Windows driver.
Signed-off-by: Olli Salonen <olli.salonen@iki.fi>
Reviewed-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/tuners/si2157.c

@@ -238,6 +238,9 @@ static int si2157_set_params(struct dvb_frontend *fe)
 		bandwidth = 0x0f;
 
 	switch (c->delivery_system) {
+	case SYS_ATSC:
+			delivery_system = 0x00;
+			break;
 	case SYS_DVBT:
 	case SYS_DVBT2: /* it seems DVB-T and DVB-T2 both are 0x20 here */
 			delivery_system = 0x20;