zl3073x_read_u48
rc = zl3073x_read_u48(zldev, ZL_REG_DPLL_DF_OFFSET(index), &val);
int zl3073x_read_u48(struct zl3073x_dev *zldev, unsigned int reg, u64 *val);
rc = zl3073x_read_u48(zldev, reg, &phase_offset);
rc = zl3073x_read_u48(zldev, ZL_REG_REF_PHASE_OFFSET_COMP,