pvr2_hdw_get_unit_number
int nr = pvr2_hdw_get_unit_number(hdw);
int pvr2_hdw_get_unit_number(struct pvr2_hdw *);
pvr2_hdw_get_unit_number(sfp->channel.hdw));
unit_number = pvr2_hdw_get_unit_number(hdw);