t4_filter_field_width
int t4_filter_field_width(const struct adapter *adap, int filter_field);
mask = (1 << t4_filter_field_width(adap, i)) - 1;
hashmask >>= t4_filter_field_width(adap, i);
nbits += t4_filter_field_width(adap, i);
width = t4_filter_field_width(adap, i);