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.