[media] cxd2820r: Update frontend capabilities to advertise QAM-256

This is supported in DVB-T2 mode, so added to the T/T2 frontend.
Signed-off-by: Steve Kerrison <steve@stevekerrison.com>
Acked-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/cxd2820r_core.c

@@ -855,7 +855,8 @@ static struct dvb_frontend_ops cxd2820r_ops[2] = {
 				FE_CAN_FEC_3_4 | FE_CAN_FEC_5_6 |
 				FE_CAN_FEC_7_8 | FE_CAN_FEC_AUTO |
 				FE_CAN_QPSK | FE_CAN_QAM_16 |
-				FE_CAN_QAM_64 | FE_CAN_QAM_AUTO |
+				FE_CAN_QAM_64 | FE_CAN_QAM_256 |
+				FE_CAN_QAM_AUTO |
 				FE_CAN_TRANSMISSION_MODE_AUTO |
 				FE_CAN_GUARD_INTERVAL_AUTO |
 				FE_CAN_HIERARCHY_AUTO |