ZERO_BASED
sc->regs.cap_lo = (ZERO_BASED(sc->max_qentries) & NVME_CAP_LO_REG_MQES_MASK) |
(ZERO_BASED((sc)->num_squeues) & 0xffff) | \
(ZERO_BASED((sc)->num_cqueues) & 0xffff) << 16