Update dvb_frontend.h

	/* new CELL-ID and NETWORK-ID */
	int (*read_cellid)(struct dvb_frontend* fe, u16* cellid); /*DVB-H DVB-T2 and DVB-T*/
	int (*read_net_id)(struct dvb_frontend* fe, u32* net_id); /* DVB-T2*/

for DVB-H/T/T2