RDMA/irdma: Prevent some integer underflows

In the Linux kernel, the following vulnerability has been resolved: RDMA/irdma: Prevent some integer underflows My static checker complains that: drivers/infiniband/hw/irdma/ctrl.c:3605 irdma_sc_ceq_init() warn: can subtract underflow 'info->dev->hmc_fpm_misc.max_ceqs'? It appears that "info->dev->hmc_fpm_misc.max_ceqs" comes from the firmware in irdma_sc_parse_fpm_query_buf() so, yes, there is a chance that it could be zero. Even if we trust the firmware, it's easy enough to change the condition just as a hardenning measure.