fbnic_stat_rd64
stat->u.old_reg_value_64 = fbnic_stat_rd64(fbd, reg, offset);
new_reg_value = fbnic_stat_rd64(fbd, reg, offset);
u64 fbnic_stat_rd64(struct fbnic_dev *fbd, u32 reg, u32 offset);
new_reg_value = fbnic_stat_rd64(fbd, reg, 1);